Aortic annuloplasty ring

ABSTRACT

An annuloplasty ring to resize a dilated aortic root during valve sparing surgery includes a scalloped space frame having three trough sections connected to define three crest sections. The annuloplasty ring is mounted outside the aortic root, and extends in height between a base plane and a spaced apart commissure plane of the aortic root. At least two adjacent trough sections are coupled by an annulus-restraining member or tether that limits the maximum deflection of the base of the annuloplasty ring. In use, the tether is preferably located in proximity to the base plane of the aortic root. The annuloplasty ring is movable between a first, substantially conical configuration occurring during a diastolic phase of the cardiac cycle, and a second, substantially cylindrical configuration occurring during a systolic phase of the cardiac cycle.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 11/183,939,filed Jul. 19, 2005 (pending) which claims the benefits of U.S.Provisional Patent Application Ser. No. 60/588,745 filed on Jul. 19,2004 (expired), the disclosures of which are hereby incorporated byreference herein.

FIELD OF THE INVENTION

The present invention relates to the general field of implantablecardiac devices, and is particularly concerned with annuloplasty devicesthat may be used to correct valvular insufficiency in valve-sparingprocedures.

BACKGROUND OF THE INVENTION

Aortic root dilation is one of the most common causes of aortic valveincompetence in North America. Prevalence of surgical corrections forthis pathology has increased considerably during the last two decades.Mechanisms involved in this pathology have been experimentally andclinically studied resulting in a variety of surgical corrections. Whilesome of the surgical corrections are better adapted to the aorticphysiology, others, less convenient, have been associated with recurrentaortic disease and valvular insufficiency. There is room for improvementin providing a surgical correction that respects the normal aortic rootphysiology in the correction of aortic valve insufficiency associated toaortic annulo-ectasia, aortic aneurysm and other such dilatations.

As is well known, the mammalian heart is an organ made up of fourmuscular chambers that function together to pump blood throughout thebody. Each of the four chambers has an associated downstream one-wayvalve made up of movable, coapting leaflets or cusps which cooperate toprevent the backward flow of blood, or regurgitation, into theirrespective chambers. Two such heart valves, the aortic and pulmonaryvalves, also commonly known as the semilunar valves, are characterizedby three leaflets or cusps. The aortic valve leaflets are attachedwithin the aortic root, to a tri-scalloped or triple scalloped line ofcollagenous, fibrous tissue generally referred to as the valve annulus.As such, a three-pointed crown-like structure serves to support theaortic valve cusps or leaflets. The U-shaped convex lower edges of eachleaflet are attached to, and suspended from, the base of the aorticroot, with the upper free edges or margins of each leaflet being free tomove and project into the lumen of the aorta. Two adjacent leafletsapproach one another at one of the three points of said crown-likestructure to define a commissure of the aortic valve. Behind eachleaflet, the aortic vessel wall bulges outward, forming a pouch-likedilatation known as the sinus of Valsalva. In the region locatedslightly above the level of the commissures, the aortic root creatingthe sinuses of Valsalva merges into the substantially tubular portion ofthe ascending aorta at a substantially planar transition zone commonlyknown as the sinotubular junction (STJ). The aortic root houses theaortic valve structure and generally includes the portion of the nativeaortic conduit extending form the left ventricular outflow tract (LVOT)to the portion of ascending aorta (AA) slightly above the sinotubularjunction. Typically, aortic root reconstructions or interventionsusually involve the aortic valve, while ascending aorta interventionsusually exclude the aortic valve and involve the native aortic conduitlocated generally downstream of the sinotubular junction.

During ventricular systole, the leaflets are passively thrust upward andoutwardly away from the centre of the aortic lumen, while in asynchronous manner, the commissures move out radially with the aorticroot. As such, the free edges of the leaflets are no longer in contactwith each other as they assume a triangular geometric relationship whenviewed along the axis of the aortic lumen. This may also be referred toas triangulation of the valve leaflets (FIG. 2C). During ventriculardiastole, the leaflets fall passively into the lumen of the aorta, andcoapt at their respective free edges to support the column of bloodabove. In a synchronous manner, the commissures move radially inwardwith the aortic root, thereby allowing the free edges to resume contactwith each other and assume a Y-shaped geometric relationship (FIG. 2B).This may also be referred to as coaptation of the valve leaflets. In ahealthy aortic valve, the geometry of the leaflets and the strongfibrous tissue support thereof provide excellent approximations of theleaflets and prevent regurgitation of flow through the aortic valve. Ina diseased aorta, the dilatation of the aortic root or valve annulus, orthe aneurysm of the aortic wall, results in compromised leafletcoaptation leading to regurgitation and valve insufficiency.

The aortic valve is a critical component in maintaining adequate flow ofoxygenated blood to the rest of the body. The conduit downstream of theaortic valve, generally above the sinotubular junction, is known as theascending aorta. A number of diseases lead to dilatation of the aorticroot structure and aortic valve annulus, also called aneurysm orectasia, which in turn affects the ability of the aortic valve leafletsto coapt or close completely. This ensuing condition, known as aorticinsufficiency, can severely diminish the heart's ability to effectivelydeliver blood to the rest of the body or to the heart muscle, and canlead to serious complications and death.

Until the early 1990s, a common treatment for managing aorticinsufficiency caused by aortic root dilatation consisted of completelyresecting the aortic valve and aortic root, and replacing such nativestructures with a composite heart valve—aortic root prosthesis (i.e. anaortic valved conduit). One of the drawbacks of this surgicalintervention, known as the Bentall procedure, is that in patients havingrelatively healthy leaflets, such leaflets are sacrificed and replacedby a prosthetic valve in order to correct the aortic dilatation. Inaddition, there is a need for prolonged anti-coagulation therapy in thecase of Bentall procedures using mechanical heart valves, and a risk ofvalve degradation and reoperation in the case of Bentall proceduresusing bioprosthetic heart valves.

Some of the problems associated with a Bentall procedure have beenaddressed through the development of a surgical procedure known asaortic valve-sparing, in which the aortic root is resected above theaortic annulus, leaving a scalloped portion of native tissue, or fringe,extending slightly above the leaflets. From approximately the samestarting point, two valve-sparing procedures have evolved. The first,known as reimplantation (FIG. 26A), involves the placement of a Dacronroot prosthesis or synthetic aortic conduit over the scalloped nativetissue, where it is sutured both below the valve leaflets through thevalve annulus, and above the valve leaflets. The procedure is generallylong and difficult to perform, and often results in leaflet impact orconcussion with the walls of the Dacron prosthesis during the ejectionphase of the cardiac cycle. In addition, the absence of radialcompliance of the Dacron root prosthesis does not allow for an increasein diameter at the sinotubular junction STJ during ejection, which is animportant aspect in providing optimal blood transport while preservingvalve dynamics and valve leaflet durability. As such, the normal valvephysiology is compromised in this valve-sparing intervention.

The second type of valve sparing operation, known as remodelling (FIG.26B), involves scalloping the Dacron root prosthesis to essentiallymatch the remaining native tissue, and using a running suture to attachthe prosthesis to the native aortic root tissue. Although this methodaddresses some of the problems of the reimplantation method, it does notdirectly constrain the valve annulus diameter, which has been seen toresult in annular dilatation over time. As such, this procedure is notwell suited for resizing a dilated valve annulus, and may be limited toreplacing aneurysmal aortic tissue. Since it also relies on a Dacronvascular conduit, which is radially non-expansible, the expansion of theaortic root at level of commissures, in the plane joining thecommissures or scalloped peaks of native tissue, tends to be constrainedby the conduit fabric hoop. As such, the leaflet free edges are hinderedin assuming their triangulated relationship, since the plane containingthe STJ is generally not expansible in this surgical procedure. Unlikethe reimplantation procedure, however, the leaflets have a lowerlikelihood of hitting the conduit wall since pseudo-sinuses may befashioned from a scalloped Dacron conduit to recreate the pouch-likeconfiguration seen in a healthy aortic root. Nonetheless, in theremodelling valve-sparing intervention, the normal native valvephysiology is compromised, and the effectiveness of resizing a dilatedaortic annulus, or preventing its future dilatation, with a scallopedvascular conduit remains questionable.

Although useful and widely accepted for some aortic reconstructionprocedures, conventional valve-sparing procedures and devicesnevertheless suffer from numerous drawbacks or shortcomings that aremanifested and become apparent both during the operative andpost-operative periods.

Accordingly, there exists a need for an improved aortic rootreconstruction procedure, and enabling devices, that allows correctionof a dilated aortic annulus, or replacement of aneurysmal aortic tissue,while preserving the native leaflets and maintaining normal valvephysiology. Typical prior art devices and methods for aorticreconstruction or valve sparing interventions do not offer a dynamicdevice configuration that may advantageously vary during the differentphases of the cardiac cycle, and consequently restore or preserve normalaortic valve physiology. More specifically, there exists a need for suchan aortic reconstruction device which, when implanted, dynamicallycontrols the valve annulus both at the level of the aortic root base,and at the level of the valve commissures, thereby leading to optimalblood flow conditions therethrough and leaflet durability. Alsobeneficial would be a procedure with reduced time and difficultyrelative to current valve sparing procedures.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide such animproved device and associated surgical method for aortic valve-sparingprocedures, or other aortic root reconstruction surgeries.

Advantages of the present invention include that the proposedannuloplasty ring, by virtue of its scalloped shape, allows fixation ofsaid ring in general proximity to the fibrous annulus of the nativevalve, and as such advantageously offers a dynamic ring design able todeflect a predetermined desired amount to modulate or control keydimensions of the aortic root, during the different phases of thecardiac cycle. As such, the proposed ring tends to preserve or restorenormal aortic root and valve leaflet physiology during aorticvalve-sparing surgeries, or aortic reconstruction surgeries. The ring isexternally placed around the aortic root, thereby tending to simplifythe surgical procedure.

The ring is provided with an annulus-restraining means orannulus-limiting structure or tether allowing the ring to move radiallyinward during muscle contractions, yet limiting or controlling themaximum diameter or dimension of the ring during phases of the cardiaccycle when the aortic root expands, in order to allow effective resizingof a dilated aortic root or valve annulus.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be disclosed, byway of example, in reference to the following drawings in which:

FIG. 1A, in a side elevational view, illustrates a prosthetic ring inaccordance with an embodiment of the present invention;

FIG. 1B, in a top view, illustrates the prosthetic ring shown in FIG. 1Ain a first ring configuration, the prosthetic ring assuming this firstconfiguration at a time interval during a diastolic phase of a cardiaccycle;

FIG. 1C, in a top view, illustrates the prosthetic ring shown in FIG. 1Ain a second ring configuration, the prosthetic ring assuming this secondconfiguration at a time interval during a systolic phase of a cardiaccycle;

FIG. 2A, in a side elevational cross-sectional view, illustrates anaortic root with its associated anatomic structures onto which theprosthetic ring of FIG. 1A will be implanted in accordance with theprinciples of the present invention;

FIG. 2B, in a top view, illustrates the aortic root shown in FIG. 2A ata time interval during a diastolic phase of a cardiac cycle, with theleaflet or cusps of the aortic valve in a coapted closed leafletconfiguration;

FIG. 2C, in a top view, illustrates the aortic root shown in FIG. 2A ata time interval during a systolic phase of a cardiac cycle, with theleaflet or cusps of the aortic valve in a triangulated open leafletconfiguration;

FIG. 3A, in a schematic perspective front view, illustrates an aorticroot having been resected to remove the portion of aortic root tissueabove the valve leaflets till the ascending aorta, the remainingscalloped aortic root readied for receiving prosthetic ring according tothe principles of the present invention;

FIG. 3B, in a schematic perspective cutaway rear view, illustrates aprosthetic ring according to the present invention having beensurgically implanted onto the scalloped aortic root illustrated in FIG.3A;

FIG. 4, in a perspective view, illustrates a first embodiment of aprosthetic ring according to the present invention;

FIG. 5, in a perspective cutaway view, illustrates internal componentsof the prosthetic ring shown in FIG. 4;

FIG. 6, in a perspective view, illustrates an undulated or scallopedring structure of the prosthetic ring shown in FIG. 4 in accordance withthe present invention;

FIGS. 7A-7E, in a cross-sectional view, illustrate alternativeembodiments of frame member and elastomeric sheath geometries of aprosthetic ring according to the present invention;

FIGS. 8A-8C, in a perspective view, illustrate alternative embodimentsof end fittings of a prosthetic ring according to the present invention;

FIGS. 9A-9E, in an elevational front view, illustrate alternativeembodiments for an end fitting arrangement that connects two adjacentposts of a prosthetic ring according to the present invention;

FIGS. 10A-10C, in a perspective view, illustrate alternative embodimentsfor the terminal end of a prosthetic ring post according to the presentinvention;

FIGS. 11A-11C, in a sectional view, illustrate alternative embodimentsfor the mechanical connection between prosthetic ring post and endfitting of a prosthetic ring according to the present invention;

FIG. 12A-12C, in an elevational view, illustrate alternative embodimentsfor an annulus-restraining means or annulus-limiting structure of aprosthetic ring according to the present invention;

FIG. 13A-13C, in an elevational view, illustrate alternative embodimentsfor an annulus-restraining means or annulus-limiting structure of aprosthetic ring according to the present invention;

FIG. 14A, in a perspective view, illustrates a second embodiment for aprosthetic ring according to the present invention;

FIGS. 14B-14C, in a partial cross-sectional view, illustrate the spatialrelationship between the prosthetic ring shown in FIG. 14A and anannulus-restraining hoop thereof;

FIGS. 15A-15B, in a partial elevational view, illustrate a thirdembodiment for a prosthetic ring according to the present invention, theprosthetic ring having a hook-in-link annulus-restraining means;

FIGS. 16A-16C, in a schematic view, illustrate an alternative embodimentfor a hook-in-link annulus-restraining means of a prosthetic ring, theannulus-restraining means applying a progressively changing restrainingforce as a function of the prosthetic ring deflection;

FIGS. 17A, in a partial elevational view, illustrate a fourth embodimentfor a prosthetic ring according to the present invention, the prostheticring having an annulus-restraining means including a shackle member;

FIG. 18A-18B, in a partial elevational view, illustrate a fifthembodiment for a prosthetic ring according to the present invention, theprosthetic ring having an annulus-restraining means configured as a webbetween two adjacent U-shaped frame members of the prosthetic ring;

FIG. 19A-19B, in a perspective elevational view, illustrate respectivelya prosthetic ring having a strap-like tether and a webbed tetheraccording to the present invention;

FIG. 19C-19D, in a schematic top view, illustrate the base portion ofthe prosthetic rings shown in FIGS. 19A and 19B, in a first ringconfiguration and a second ring configuration, respectively.

FIG. 20A-20C, in an elevational side view, illustrate a prosthetic ringaccording to the present invention, and more specifically the wire framestructure thereof, respectively in a free-state non-implantedconfiguration, a first implanted ring configuration occurring at a timeinterval during the diastolic phase of the cardiac cycle, and a secondimplanted ring configuration occurring at a time interval during thesystolic phase of the cardiac cycle, the mating anatomic structures notbeing shown;

FIG. 21A, in a graphical view, illustrates the varying dimensions of adynamic aortic root as a function of the different phases of the cardiaccycle;

FIGS. 21B-21G, in a schematic diagrammatic view, illustrate thegeometrical relationship between the base and top dimensions of aprosthetic ring, at discrete time intervals of the cardiac cyclegraphically represented in FIG. 21A;

FIGS. 22A-22C, in perspective elevational views, illustrate a sixthembodiment for a prosthetic ring according to the present invention, theprosthetic ring incorporating a vascular conduit portion;

FIG. 23A-23C, in perspective elevational views, illustrate a seventhembodiment for a prosthetic ring according to the present invention, theprosthetic ring being designed for implantation through an endoscopicprocedure, avoiding the need to incise the aorta for placement thereof;

FIGS. 24A-24D, in a schematic cutaway view, illustrate variants forsuturing the prosthetic ring according to the present invention to ascalloped aortic root portion similar to the one shown in FIG. 3A;

FIGS. 25A-25B, in a schematic cutaway view, illustrate variants forsuturing the prosthetic ring and conduit arrangement shown in FIG. 22Ato a scalloped aortic root portion similar to the one shown in FIG. 3A;

FIG. 26A-26B, in a perspective elevational view, illustrate currentsurgical reconstructions of the aortic root as references, without theuse of a prosthetic ring according to the present invention.

DETAILED DESCRIPTION

Although the devices according to the present invention are disclosedherein as being used in the context of an aortic valve repair orreconstruction, the devices may also be used in any other contextsincluding surgical procedures of other semi-lunar valves, such as thepulmonary valve, or in the repair of other valve-containing conduits,without departing from the scope of the invention.

Referring to FIGS. 1A-1C, there is shown an aortic annuloplastyprosthesis or prosthetic ring 1 according to an embodiment of thepresent invention. The prosthetic ring 1 is non-planar and extends inheight between a base plane (labelled BASE) and a top plane (labelledTOP). The prosthetic ring 1 resembles a crown-like structure havingthree circumferentially spaced apart undulations or scallops. Threegenerally concave, U-shaped trough sections 201 emanate from the base206 of the ring 1 and extend axially away from said base, terminating inthree spaced apart crowns or crest sections 202 at the top 207 of ring1. As such, three alternating sinus-zones or cusp-zones 203 aredelimited. Each cusp-zone 203 is generally located within one of saidthree trough sections 201, and extends below plane TOP. As well, threeinfra-commissure, inter-leaflet triangles or zones 204 are alsodelimited. Each inter-leaflet zone 204 is located generally below one ofsaid three crest sections 202 and generally above plane BASE. Eachinter-leaflet zone 204 generally extends between two adjacent troughsections 201.

In proximity to the plane BASE, is provided an annulus-restraining,annulus-limiting means or structure in the nature of three spaced-apartbrace members 400. Each of said brace members spans to connect each oftwo adjacent trough sections 201. Said brace members 400 and inferior orbase portions 208 of said trough sections 201 together forming acontinuous perimeter 205 (FIG. 19C) in proximity to the base 206 of ring1. As will be described in greater detail below, said perimeter 205provides a radially compliant or conformant structure at the base 206 ofring 1 during the different phases of the cardiac cycle, but also byvirtue of said brace members restrains or limits the maximum diameterthat the aortic root can assume during the cardiac cycle. As such,surgical correction of a dilated aortic root, or aneurysmal aortictissue, may be achieved through implantation of said prosthetic ring 1according to the principles of the present invention.

With reference to FIGS. 2A-2C, the shape or profile of prosthetic ring 1approximates the non-planar, scalloped line of collagenous, fibroustissue forming the native annulus 92 of aortic valve 94. During thesurgical intervention, ring 1 is affixed to the exterior of the aortaand aortic root 90, in close proximity and in register with the nativevalve annulus 92. Preferably, ring 1 is affixed in line with, orslightly below, the native valve annulus 92 using conventionaltechniques such as sutures. For instance, after surgical implantation,points “b” located at the base 206 of ring 1 (and located generallywithin plane BASE) will be in close proximity to, or in register with,points “B” designating the portion of native valve annulus 92 at thebase 97 of the aortic root 90, located below the nadir of the valveleaflet 912 and in close proximity to the left ventricular outflow tract(labelled LVOT). Similarly, after surgical implantation, points “c”located on crest sections 202 of ring 1 (and located generally withinplane TOP), will be in close proximity to, or in register with, points“C” designating the portion of the native valve annulus 92 at the levelof the leaflet commissure 96; points “a” and “d” lying on the U-shapedtrough sections 201 of ring 1, will be in close proximity to, or inregister with, points “A” and “D”, respectively, designating the portionof the native valve annulus 92 located substantially at mid heightbetween the commissures 96 and base 97 of aortic root 90. As such,because ring 1 is affixed or sutured in close proximity to fibrous valveannulus 92, ring 1 can advantageously serve to resize aortic root 90,and valve annulus 92 contained therein, thereby allowing surgicalcorrection of annulo-ectasia, aneurysm in the aortic root, or other likedilatations occurring in the native aortic tissue. As well, theattachment of ring 1 in generally close proximity to valve annulus 92allows ring 1 to suitably regulate the geometry of aortic root 90, andspatial relationship of valve leaflets 912 during the different phasesof the cardiac cycle, thereby tending to preserve or restore normalvalve physiology through valve-sparing surgical procedures.

Referring to now FIG. 3A, is illustrated a scalloped aortic root 91having been readied for valve-sparing surgical intervention by surgicalresection of the aortic tissue that forms the sinuses of Valsalva, priorto implantation of ring 1. Typically, in resecting the aortic root 90, amargin or fringe 910 of aortic root tissue will be maintained, saidfringe extending generally above the valve leaflets 912 and forming ascalloped free edge 911 of aortic root tissue.

As schematically illustrated in FIG. 3B, ring 1 is placed on theexterior of scalloped aortic root 91. As illustrated, in a sectioningplane in proximity to the leaflet nadir, the sectioned portion 209 ofring 1 lies adjacent to the fibrous native annulus 92, at the base 97 ofthe aortic root 91 and slightly above LVOT. On the posterior,non-sectioned portion of aortic root as illustrated in FIG. 3B, U-shapedsection 201 of ring 1 will lie adjacent fibrous annulus 92 (shown as adashed line), as said fibrous annulus rises above the base 97 of aorticroot 91 to point “C”.

An externally placed annuloplasty ring, such as ring 1 according to thepresent invention, tends to facilitate or simplify the surgicalvalve-sparing procedure. Since ring 1 is external, a less-precise ringshape that only has to approximate the valve annulus 92 may beimplanted, since the potential for leaflet-to-ring interference iseliminated with an externally implanted ring. Conversely, an internallyplaced annuloplasty ring, as is the case with mitral and tricuspid valveannuloplasty rings, must very closely follow the native aortic annulus(and leaflet attachment perimeter) in order to avoid leaflet-to-ringinterference or other such contact that may compromise leafletphysiology, leaflet coaptation, or effective blood flow therethrough.Given the complex, non-planar geometry of the aortic valve andconsidering the anatomic variation between patients, fashioning such aninternal aortic annuloplasty ring may prove impractical and fastidiousto surgically implant.

Moreover, an externally placed annuloplasty ring according to thepresent invention provides other advantages. By abutingly contacting theexterior surfaces of aortic root 90, ring 1 provides a bearing surfaceacting as a restraint or buttress capable of resizing a dilated aorticroot annulus by exerting a constraining load on the dilated portion ofnative tissue. As such, the load imposed by the native tissue onring-securing sutures (or alternatively other means of ring fixation)tends to be minimized hence also reducing the criticality of saidsutures (or other fixation means) in securely maintaining the resizedaortic root annulus. Conversely, in an internally placed annuloplastyring, the sutures are exposed to greater tensile stresses as the dilatednative tissue is urged to conform to the smaller annuloplasty ringsolely by said sutures. Furthermore, since the resizing load istransmitted through the sutures, the native tissue is exposed to largerconcentrated pressures at the relatively small suture interface. Thismay lead to tissue trauma or suture tear-through. In comparison, inexternally placed annuloplasty rings, the ring structure provides arelatively larger and evenly distributed contact or bearing surface tothe dilated native tissue. This tends to reduce concentrated contactstresses exerted on the dilated or oversized native tissue, and reducesthe likelihood of inducing tissue trauma or suture pullout.

FIG. 3B also schematically illustrates a tubular vascular conduit 95associated with an aortic valve-sparing procedure. Conduit 95 serves toreplace the aneurysmal aortic tissue having been resected above thevalve annulus 92 thereby recreating: (a) pseudo-sinuses of Valsalva, (b)the aortic conduit at the level of STJ, and (c) to the extent necessary,the portion of ascending aorta having been resected at the start of thesurgical intervention. Variants of conduit 95, and more specifically thedesign features and construction of said variants to allow advantageouscooperation with ring 1 according to the principles of the presentinvention, will be described in greater detail below and in reference toFIGS. 22A-22C. Alternatively, in the case of aortic annulo-ectasia withhealthy aortic root tissue, the aorta may be incised, ring 1 may then beimplanted over the aortic root 90 to resize the dilated valve annulus 92without resecting the aortic root, and the incised ends of the aortareattached to one another, without the need for a vascular conduit.

Referring now to FIGS. 4-6, a first embodiment of ring 1 will bedescribed in greater detail. Ring 1 consists of an undulated orscalloped three-peak ring structure, or space frame 200 and anannulus-restraining means or annulus-limiting member 400. Frame 200 isconfigured to form a closed, non-planar, continuous band including threetrough sections 201 located in proximity to ring plane BASE, and threecrest sections 202 located in proximity to ring plane TOP. Said crestsections are circumferentially interspersed between said troughsections. Said undulated space frame 200 is preferably constructed fromthree substantially U-shaped frame members 210. Said three frame members210 are connected at the three resulting crests sections 202 at top 207of ring 1 by three crown plates, end connectors, or fittings 300, andcoupled at the base 206 of ring 1 by three hoop-closing members,tethers, ties or restraints 401.

Each of U-shaped frame members 210 is defined by a concave base 211 fromwhich extend two upstanding substantially arcuate beams, wires or posts212. When ring 1 is in its non-implanted, stress-free state, posts 212extend in a direction generally normal to plane BASE and in a tapering,radially-inward fashion, such that the crest sections 202 are generallyin closer proximity to each other than the trough sections 201.According to the principles of the present invention, such spatialrelationship between said crest and trough sections is designed to varyat different times during the cardiac cycle, as will become apparent andexplained in greater detail below.

U-shaped profile of members 210 (and more generally the resulting troughsection 201) is configured to approximate or resemble the shape of thenative valve annulus 92 over one leaflet 912, such that when implanted,said U-shaped members 210 will rest in proximity to, and generally inregister with, valve annulus 912 to facilitate fixation of ring 1thereto, preferably by sutures placed through ring 1 and valve annulus92. Variations in patient anatomy may affect the degree of proximity oralignment between said U-shaped members and said annulus afterimplantation of ring 1.

U-shaped frame member 210 is preferably constructed from a biocompatiblerelatively-flexible material such as titanium alloy, which canelastically withstand stresses when ring 1 is exposed to variableloading during the cardiac cycle. Moreover, given a relatively flexiblematerial, members 210 may be configured and sized with the requiredstructural integrity to allow predetermined deflection under suchcardiac loads, in a manner that achieves the desired modulation ofaortic root dimensions. Additionally, the material selected for framemember 210 must be capable of withstanding the desired number of fatiguecycles in order to provide failsafe performance of ring 1 for a desiredimplant life.

As illustrated in a first embodiment of the present invention (FIG. 6),the U-shaped frame member 210 is preferably constructed fromtitanium-alloy wire having a diameter between 0.010″ to “0.060”,preferably between 0.020″ and 0.040″, and more preferably between 0.025″and 0.035″. The cross-sectional profile of the wire and wirecross-sectional area may be varied along the length of wire in order tochange or fine-tune the dynamic behaviour of ring 1 under load, or tooptimize stress concentrations. Other metallic materials are alsopossible, such as stainless steels, cobalt alloys, Nitinol or othershape memory alloys. Depending on the material selected, the wirecross-sections and profiles may fall outside the preferable diameterrange listed above in order to account for their different materialproperties relative to titanium alloy. Polymeric materials, eitherisotropic in nature or composite in construction, are also possibleprovided their design offers the desired structural integrity andfatigue life under the deflections required for adjustment or modulationof aortic root geometry.

As illustrated in FIG. 7B, U-shaped frame members 210 are configuredfrom wire having a circular cross-section 213, tending to facilitate theconstruction of ring 1. Said frame members may also be configured fromstrip stock 214 resulting in a frame member having a generallyrectangular cross-section (FIG. 7A), or from tube stock 215 resulting ina frame member with annular cross-section (FIG. 7C), or from bar stockwhich may be machined, forged, or formed, or from a casting or plasticinjection process to produce a frame member with a uniquecross-sectional shape such as substantially cam-shaped cross-section 216(FIG. 7D).

U-shaped frame member 210, and more specifically struts or posts 212thereof, have terminal ends 220 that are preferably enlarged or bulbousto obtain the desired mechanical joint with end fitting 300, and desiredrange of relative movement between adjacent posts 212. Some or all ofsaid terminal ends can be selectively configured such that certain typesof movement of the frame member 210 relative to end fitting 300, or withrespect to adjoining frame member 210, can be either constrained orfree. As illustrated in FIG. 6, terminal ends are substantiallyspherical or ball shaped 218. As such, spherical ball ends 218 allowball-in-socket type of movement or articulation of post 212 relative tosaid fitting 300, insofar as a gap is provided therebetween to allowsuch articulation. Spherical end 218 does however axially retain post212 relative to end fitting 300. Alternatively, as illustrated in FIG.10A, terminal end 220 may be configured with an enlarged cylindricalprotrusion 221 that is generally aligned with longitudinal axis of post212. As such, the mechanical joint between cylindrical terminal end 221and cylindrical volume within fitting 300 allows rotation 223 of post212 about its long axis, while axially retaining post 212 within fitting300. Both embodiments illustrated in FIGS. 6 and 10A may advantageouslyserve to reduce stresses in U-shaped frame member 210 during deflectionsof ring 1 occurring at different phases of the cardiac cycle. A furtherembodiment of a terminal end 220 consists of bending the terminal end ofa circular cross-section post 212. When such bent terminal end 224 iscoupled with an appropriate end fitting 300, the resulting mechanicaljoint will permit rotation 226 of said post about a rotation axis 225aligned with the centreline of bent terminal end. For example, therotation axis 225 may be either tangent to the diameter defined by threecrest sections 202 lying in plane TOP, or normal to said diameter, oreven assume an orientation between normal and tangent to said diameter.The bent terminal end 224 also serves to retain post 212 within endfitting 300. Yet another embodiment for a configuration of terminal end220, as illustrated in FIG. 10C, consists in having a cube-shapedterminal end 227, or enlarged terminal end with at least two opposedflats. Such a terminal end would essentially restrict all relativemovement between post 212 and fitting 300, provided said fitting isconfigured with an appropriate mating depression or groove to receivesaid cube-shaped terminal end 227. Other variants for a terminal end arealso possible without departing from this aspect of the invention.

Referring now to FIGS. 5 and 6, ring 1 is configured with three endfittings 300 providing a mechanical connection between adjacent U-shapedframe members 210, and more specifically terminal ends 218 of post 212thereof. Said end fittings offer many advantages. One such advantage isthat, by preventing direct contact between frame terminal end 220 andnative aortic tissue, end fittings 300 act as bearing plates or surfacestending to reduce and uniformly distribute ring contact stresses aroundthe commissures 96. Another advantage provided by fittings 300 consistsin reducing the maximum or peak bending stresses that frame member 210will experience under deflection of ring 1, by allowing relativemovement between end fitting 300 and frame terminal end 220. Yet anotheradvantage provided by end fittings 300 consists in facilitating thefabrication of a scalloped or undulated ring structure 200 by providingmechanical connection of smaller, easier to fabricate components such asframe member 210.

End fitting or crown plate 300 may be fabricated from a variety ofmetallic or polymeric materials, depending on the type of mechanicaljoint desired. In the first embodiment illustrated in FIG. 6, fitting300 is made from medical grade polymer suitable for plastic injectionmolding, such as polypropylene or PEEK, which can be over-molded toterminal ends 220 of posts 212. As previously discussed, terminal ends220 are preferably configured with one of a variety of terminal endgeometries in order to achieve the desired mechanical joint between endfittings 300 and frame member 210. Alternatively, terminal ends 220 ofadjacent frame members 210 may be: (i) welded together at a weldlocation 230 and crimped to metallic plate 231 at crimp locations 232(FIG. 9A); (ii) crimped to metallic plate 233 at crimp location 234(FIG. 9B); (iii) welded simultaneously to one another and to metallicsub-plate 235 to form a weld bead 236 (FIG. 9C); or (iv) glued to ametallic of plastic sub-plate 237 at glue location 238 (FIG. 9D).

Although less advantageous, as illustrated in FIG. 9E, terminal ends 220of two adjacent U-shaped frame members 210 may alternatively be joinedtogether by a weldment or brazed joint 239 (if metallic), or gluedtogether in a glued joint 240 (if polymeric). As such, the advantagesassociated with having a crown plate 300, as previously recited above,would not be exploited in such a ring structure. Alternatively still,the three U-shaped frame members 210 may be produced in a single,unitary piece thereby also eliminating said weld or glue joint 239, 240.

According to a first embodiment, ring 1 is preferably configured andsized such that when said ring is implanted, crown plates 300 arepreferably in register with, or in close proximity to, commissures 96.Variants of ring 1 may also be designed such that, in use, crown plates300 extend above commissures 96 and fibrous annulus 92, for exampleextending till or slightly above the level of the STJ, or alternativelybelow said commissure and annulus within inter-leaflet zone 204. As willbe discussed in greater detail below, the spatial relationship betweensaid crown plates and said commissures may have an effect on method ofsuturing.

FIGS. 8A-8C illustrate variants to the geometry, configuration or sizeof end fitting 300 that aim to optimize stress distribution and transferof loads between post 212 and end fitting 300. Said stresses and loadsare exerted on fittings 300 by U-shaped frame members 210, when saidframe members are exposed to and react cardiac loads from a dynamicaortic root 90. For example, one variant illustrated in FIG. 8A,involves extending the mechanical interface between end plate 310 andposts 250 to cover a greater length 311 of said post, in a graduallytapering manner towards base 206 of ring 1. This provides a largermechanical interface or transition zone rather than simply covering,encapsulating, or enclosing the terminal-most length 220 of said post ina manner as illustrated in previously described FIG. 6. As such, thevariant in FIG. 8A would distribute the stresses generated from thedeflections 314 of post 250 (said deflections in a plane 313 containingplate 310 and posts 250), over a larger contact or bearing surface 311at plate-to-post interface 315. Similarly, the variant in FIG. 8B woulddistribute the stresses generated from the deflections 325 of post 251(said deflections in a plane 324 that is substantially normal to plane323 containing plate 320 and posts 251), over a larger contact orbearing surface 321 at plate-to-post interface 322. In another exampleof a variant illustrated in FIG. 8C, end plate 330 is tapered at theinterpost junction 331 occurring between adjacent posts 252, 253. Such atapering feature would allow angular deflections of one post 253 about arotation axis 333 that is coincident with longitudinal axis of adjacentpost 252. One of the key aspects of the features just described withreference to FIGS. 8A-8C, is that such features allow for wire or poststresses, that are generated by relative movement or deflections betweenadjacent wires or posts, to be distributed and shared with cooperatingend fittings. This distribution and transfer of stresses to saidcooperating end fitting tends to improve fatigue life of wire or postswhen they are subjected to cyclic cardiac loading.

In controlling, modulating, or adjusting key dimensions of the aorticroot 90 following implantation of ring 1, it may be advantageous toallow relatively free or unhindered motion between wire or posts 212 andend fitting 300, said relatively free motion being within apredetermined range of motion resulting from the design interfacebetween said post and said end fitting. In one embodiment according tothis aspect of the invention, as illustrated in FIG. 11A, fitting 340 isconfigured with a clearance channel 341 extending longitudinally over alength 342 of wire or posts 259, said channel 341 having a width largerthan said wire or post thickness. The width of channel being larger thanthe wire or post thickness results in a predetermined range ofrelatively free angular deflection 343 within which wire or post 259 canangularly deflect before contacting channel walls 344 (i.e. angularrange of freedom). Preferably, said channel width is tapering in size aschannel 341 approaches post-to-fitting encapsulation zone 345.

In another embodiment according to this aspect of the invention, asillustrated in FIG. 11B, end fitting 350 is configured with two keyways351. Each of wires or posts 254 is configured with an appropriatelyshaped cooperating key 255 that allows rotation of said key within saidkeyway due to a preset clearance therebetween. The angle of keywaysector 352 being larger than the angle of key sector 256 results in apredetermined range of relatively free angular deflection 353 withinwhich said key can rotate within said keyway before it contacts stops354. As such, post 254 can rotate about its longitudinal axis apredetermined amount before contacting stops 354 (i.e. torsional rangeof freedom).

In yet another embodiment according to this aspect of the invention, asillustrated in FIG. 11C, end fitting 360 is configured with two elongatechannels or trackways 361 extending along length 362 of fitting 360 in adirection substantially aligned with height 363 of ring 1. Trackway 361is configured and sized such that terminal ball end 257 of wire or post258 is slidingly engaged therewithin. This allows relatively freetranslational movement of wire or post 258 relative to end fitting 360,within a predetermined range of translational motion, said predeterminedrange limited by terminal ball end 257 coming into contact with eitherstop 363 or trackway top 364 (i.e. linear or translational range offreedom). Such an embodiment is advantageous in providing a ring 1 witha variable height 363.

A post-to-fitting design interface as described above in reference toFIGS. 11A-11C, will also have the effect of distributing or transferringpost stresses to cooperating fitting, only after a deflectiontherebetween exceeds said predetermined range of relatively freemovement, and post, or terminal end thereof, comes into contact withmotion-limiting features of said fitting. These features may becombined, or used individually, to control, modulate, or limit keydimensions of aortic root 90 during the cardiac cycle.

In another aspect of the present invention, illustrated in FIG. 19B,crown plate 300 may be advantageously provided with an aperture 370 toallow suturing of ring 1 at commissures 96. Moreover, aperture 370, alsoextending through crest section 202 of ring 1, may also advantageouslyprovide a fixturing means for demountably engaging ring 1 with anannuloplasty ring holder (not shown), said holder serving to hold andmanipulate ring 1 during surgical implantation thereof. Said holder maybe configured and sized for engaging said apertures 370 preferably whilesimultaneously spreading apart crest sections 202 (relative to theirnon-stressed, free state configuration) thereby tending to facilitateimplantation of ring 1. Alternatively, aperture 370 may be replaced by ablind hole or any other suitable mechanical interface capable ofproviding demountable engagement with an annuloplasty ring holder.

In a first embodiment of the present invention (FIG. 5), structure orframe 200 is preferably covered by a substantially elastomeric covering,layer or sheath 500. Elastomeric layer 500 is preferably manufacturedfrom a biocompatible material such as silicone rubber, polyurethane,synthetic or natural rubber approved for implant use, elastic hydrogels,polyvinyl alcohol, or other like substantially elastic biocompatiblematerials that do not considerably rigidify the structure of underlyingU-shaped frame member 210. In a first embodiment of the presentinvention, elastomeric layer 500 is enveloped or covered by an outertextile or fabric covering 600.

Elastomeric layer 500 provides a variety of functions and advantages.One function of said elastomeric layer is to provide an improved orincreased contact area between ring 1 and aortic root 90. As well, dueto its elastomeric material properties, said layer provides a relativelysofter, less traumatic, cushioned contact surface with aortic roottissue than the stiffer, metallic U-shaped frame member 210. Anotherfunction of elastomeric layer 500 is to provide volume between therelatively thin frame member 210 and fabric covering 600, so as to limitor prevent unwanted tissue ingrowth that may otherwise occur in theresulting space or residual volume between member 210 and covering 600in the absence of elastomeric layer 500. A further advantage offered bysaid elastomeric layer is to enhance suture pullout strength of ring 1,while reducing loading on fabric covering 600, when ring fixationsutures are placed through said elastomeric layer. In a furtheradvantage still, elastomeric layer 500 may be used as a biocompatiblecovering to shield an underlying core material that may exhibit inferiorbiocompatibility. For instance, the elastomeric layer may cover the endfittings 300 of ring 1 if said fittings exhibit inferiorbiocompatibility. The elastomeric layer 500 may also be advantageouslyused to cover all constituent parts of a composite ring structure,thereby providing a containment envelop or encasement capable oftrapping said constituent parts in the event of a ring failure orrupture between said constituent parts. Finally, elastomeric layer 500may be applied strategically to U-shaped frame member 210, either atselect locations or in varying thicknesses, so as to tune the dynamicresponse of scalloped ring structure 200.

With reference to FIG. 5, elastomeric layer 500 preferably covers theU-shaped wire frame 210 and end fittings 300. Elastomeric layer orsheath 500 may be applied to underlying structure and more specificallyU-shaped frame member 210 in a variety of thicknesses andcross-sectional shapes in order to best exploit one or several of theadvantages described above. For example, elastomeric layer 500 may beapplied with a uniform thickness around the underlying frame member 210,resulting in a cross-sectional shape of elastomeric layer 500 beingsimilar to that of said frame member except for being equally offsettherefrom by the sheath thickness. For example, FIG. 7A illustrates anembodiment having an elastomeric layer 501 with substantiallyrectangular outer profile achieved by having an equal thicknesselastomeric sheath around a substantially rectangular core 214; FIG. 7Billustrates an embodiment having an elastomeric layer 502 withsubstantially circular outer profile achieved by having an equalthickness elastomeric sheath around a substantially circular core 213;FIG. 7D illustrates an embodiment having an elastomeric layer 504 withsubstantially tear-drop outer profile achieved by having an equalthickness elastomeric sheath around a substantially cam-shaped core 216.

Alternatively, said elastomeric sheath thickness may be of variablethickness around said core or underlying frame structure resulting in asheath cross-sectional shape that is unevenly offset, or completelyunrelated to the frame cross-sectional shape. For example, FIG. 7Cillustrates an embodiment having an elastomeric layer 503 withsubstantially elliptical outer profile achieved by having an unequalthickness elastomeric sheath around a substantially tubular core 215;FIG. 7E illustrates an embodiment having an elastomeric layer 505 withsubstantially crescent-shaped outer profile achieved by having anunequal thickness elastomeric sheath around a substantially circularcore 217.

The embodiments illustrated in FIGS. 7C and 7E, in addition to providingan increased bearing surface of the ring structure 200 against theaortic wall, or aortic root conduit, have the additional benefit ofproviding a larger area through which to apply ring fixation sutures.Furthermore, the embodiment of FIG. 7E provides the additional benefitof closely conforming to the native anatomy of the aortic root 90 byhaving a generally concave tissue-contact surface 219.

With reference to FIG. 5, an outer textile layer or fabric covering 600preferably covers elastomeric layer 500. Textile layer 600 is preferablymade from materials including, but not limited to, polyester,polypropylene, polytetrafluoroethylene (PTFE), microporous expandedpolytetraflouroethylene (ePTFE), polyethylene terephthalate (Dacron),polyamide (Nylon), polyethylenterephthalate (PET), or other like fabricsappropriate for implant use. Said textile layer may also beadvantageously treated with bioactive agents or surface treatments tolimit foreign body response and promote favourable tissue ingrowth afterimplantation of ring 1. Preferably, said textile layer or fabriccovering is between 0.005″ and 0.020″ in thickness. One function offabric covering 600 is to provide a means for suturing the implantablering 1 to native anatomic tissue, or to an aortic root prosthesis thatmay be used in conjunction with ring 1. Another purpose of said fabriccovering is to provide a suitable surface for the post-implantationgrowth of cells and tissue, helping to mitigate long-term foreign-bodyresponse and reduce the likelihood of infection and other complications.

With reference to a first embodiment of the present invention, and toFIGS. 1A through 5, the annulus-restraining means or annulus-limitingstructure 400 and the function it provides will now be discussed ingreater detail.

The main function of annulus-restraining means 400 is to limit themaximum diameter or dimension at the base 206 of ring 1, while allowingsubstantially unhindered radially inward deflections at ring base 206.Deflections at ring top 207, both radially inward and outward, arepreferably substantially unhindered by said means 400. As such, sincering 1 is secured during surgery to aortic root 90, and morespecifically valve annulus 92 thereof, ring 1 also adjusts thedimensions of aortic root 90, controls the variations of saiddimensions, or limits deformations thereof, said adjustment or controlgoverned at least in part by said means 400.

Annulus-restraining means 400 extends from one U-shaped trough section201 to an adjacent U-shaped trough section 201, spanning acrossinterleaflet zone 204 therebetween (FIG. 1A-1C). Preferably, asillustrated, each of three interleaflet zones 204 (delimited by dashedline perimeter in FIG. 4) is spanned by an annulus-restraining means orstructure 400. Alternatively, variants of ring 1 may also be configuredhaving annulus-restraining means or structure 400 that only spans acrossone, or two, of the three said interleaflet zones 204.

In FIG. 4, in a preferred first embodiment of ring 1, is illustrated anannulus-limiting structure or annulus-restraining means 400 in thenature of a hoop-closing member, tie, restraint, strap or tether 401.

Tether 401 may be constructed from a textile or fabric structure that isconfigured with a plurality of pleats 402 to allow controlled expansionor limited deformation of ring 1, and more specifically base 206thereof, in a direction generally perpendicular to the axis defining thefold of said pleats. Fabric tether 401 may be either an integralcomponent woven or knit directly into the fabric covering 600 of ring 1,or may be independently woven, knit, or produced and subsequentlyassembled to ring 1 as an additional part or component. By configuringsaid tether 401 with an appropriate number, geometry and depth of pleat402, ring 1 can be made to be expansible up to a limit point when saidpleats are substantially flattened or unfolded, at which point ring 1,and aortic root 91 attached thereto, would be limited, restrained ormodulated from further expansion.

During contraction of the heart muscle near the outflow tract LVOT, andmore specifically during annulus-reducing contraction of aortic rootbase 97, pleats 402 resume their folded or pleated configuration. Assuch, pleats 402 impose little or no restraint on ring 1 as it deflectsradially inward during said contractions, thereby allowing the ring 1 tocontract at base 206 and assume a smaller diameter or size in compliancewith the aortic root. This behaviour of ring 1 generally reflects thenormal physiology of the aortic root 90, whose dimension or geometry isdynamic, and varies as a function of ventricular muscle relaxation orcontraction and blood pressures within said aortic root. Folding actionof pleats 402 would allow ring base 206 to decrease in diameter, ordimension, up to its predetermined minimum, and substantially withoutinterference to surrounding body tissues. Pleating, as such, eliminatesthe formation of larger folds in textile or fabric structures, or otherlike structures, when ring 1 deforms. Formation of larger folds maynegatively affect tissue ingrowth into portions of implanted ring 1, ormay insult surrounding tissue as said larger folds accommodate saidcontraction of ring base 206.

Tether 401 is designed to act primarily when it is exposed to a tensileload, such tensile load occurring typically when aortic root 90 wants toexpand during the variable cardiac cycle. Tether 401 is designed to havelittle or substantially no effect on radially inward deflections ofaortic root tissue, especially in said deflections occurring withininterleaflet triangle 98 of said aortic root (FIG. 3A).

As such, the base diameter 97 of aortic root 91 (and of valve annulus92) may be regulated or controlled by tether 401 which allowssubstantially unhindered radially inward deflections of aortic roottissue, but limits the maximum base diameter 97 with the aim of resizingthe dilated native aortic root 90, restoring leaflet 912 coaptation, andcorrecting aortic insufficiency or regurgitation. During said radiallyinward deflections of aortic root tissue, trough sections 201 movecloser together as tether 401 allows native aortic tissue, especially ininterleaflet triangle 98, to contract or deflect inwardly. Duringradially outward deflections of aortic root tissue, ring base 206 alsodeflects radially outward and trough sections 201 move apart relative toeach other, until the effect of tether 401 sets in and starts to limitand eventually restrain any such further radially outward deflections.

Tether 401 advantageously provides the ability for a scalloped ringstructure 200 to resize a dilated aortic root 90 (and dilated valveannulus 92 therein), while also preserving the flexibility and radialcompliance of said scalloped ring structure. In contrast, attempting toresize a dilated aortic root with a flexible scalloped ring structurenot benefiting from the effect of tether 401 would result in flatteningof ring scallops or undulations. Flattening of ring scallops wouldresult in a corresponding increase in diameter of ring base as saidscalloped ring is exposed to loads from an expanding pressurized aorticroot. If said scalloped ring is in turn stiffened to prevent saidunwanted flattening of scallops, the resulting structural stiffness maybe too high to allow the desired radially inward compliance of scallopedring at its base, or deflection of crest sections 202 at its top, duringthe varying cardiac cycle. As such, a stiffened scalloped ring withouttether would not allow resizing of a dilated aortic root in a mannerthat tends to preserve the normal physiology of a dynamic native aorticroot.

Preferably, as illustrated in FIG. 4, annulus-restraining means orstructure 400 is located in general proximity to base 206 of ring 1.Preferably, said means or structure 400 is located between plane BASEand one-half the height between planes BASE and TOP, and more preferablyin between one-eight to one-third of said height. Without departing fromthe spirit of the invention, variants of ring 1 may be configured withmeans or structure 400 located anywhere within substantially triangularinter-leaflet zone 204, above plane BASE and below crest sections 202.Moreover, said means or structure 400 may be configured in a variety ofsizes or dimensions within said inter-leaflet zone 204, ranging from astrip-like geometry (FIG. 19A) to a web-like geometry (FIG. 19B).

Referring now to FIGS. 12A-12C, are illustrated alternative embodimentsof an annulus-restraining means or annulus-limiting member 400 of thering 1. FIG. 12A illustrates an annulus-restraining means in the natureof a substantially stretchy, generally flexible rubber strap orelastomeric tether 402. Elastomeric tether 402 may be made from the samematerial as the elastomeric layer 500 used to cover the U-shaped framemembers 210, and as such tether 402 extends therefrom as an integralextension or link. Alternatively, elastomeric tether 402 may be madefrom a different formulation, or material, that may be overmolded,glued, or bonded to the previously produced elastomeric sheath or layer500, or to frame members 210, and as such defining a composite assemblyfor ring 1. Alternatively still, ring 1 may be configured with framemembers 210 being replaced by elastomeric layer 500.

FIGS. 12B-12C illustrate an annulus-restraining means 400 in the natureof a fibre-reinforced silicone tether 403. Silicone tether 403 is drapedbetween adjacent frame members or posts 210, said tether being ingeneral proximity to the base of the inter-leaflet triangle 204. Afibre-reinforcement 404 contained within silicone tether 403 is designedto approximate the visco-elastic behaviour of the native aortic roottissue; that is, offering compliance or flexibility with increasingstiffness as the diameter of ring base 206 increases. FIG. 12Billustrates silicone tether 403 in a non-stretched, relatively flexibleconfiguration. In this flexible configuration, said fibre-reinforcement404 provides substantially little or no stiffening. FIG. 12C illustratessilicone tether 403 in a stretched, relatively stiff configuration. Inthis stiff configuration, fibres of said fibre-reinforcement providestiffening that substantially prevents further elongation of said tether403. Optionally, silicone tether 403 may also be covered with a pleatedor crimped fabric (similar to 401) that allows said tether to stretchbetween said flexible and stiff configurations.

Referring now to FIGS. 13A-13C, are illustrated further alternativeembodiments of an annulus-restraining means or annulus-limiting member400 of the ring 1. FIG. 13A illustrates an annulus-restraining means 400in the nature of an elastically deformable undulated tie 405. Tie 405 ispreferably metallic in construction such that it can be joined orconnected to span between two adjacent metallic U-shaped frame members210. An elastic sheath 406, similar to elastomeric layer 500 used tocover U-shaped frame members 210, preferably covers tie 405. Undulations407 in tie 405 will progressively straighten out as ring 1 expands atits base 206, thereby providing a progressively increasingannulus-restraining load with increasing ring 1 diameter. Ring 1 islimited to further radial expansion when said undulations aresubstantially flattened. Tie 405 is designed with the appropriategeometry and number of undulations such that, for a predetermined rangeof ring 1 annulus expansion (and circumferential elongation of tie 405),the material properties of said tie will not be exceeded and, as such,said tie can elastically resume its undulated configuration duringvariations in the cardiac cycle. FIG. 13B illustrates anannulus-restraining means 400 in the nature of an elastically deformableloop 408. FIG. 13C illustrates an annulus-restraining means 400 in thenature of an elastically deformable spring member 409.

Referring now more specifically to FIGS. 14A-14C, there is shown aprosthetic aortic annuloplasty ring 2 in accordance with a secondembodiment of the present invention. Ring 2 is substantially similar toring 1 already described, hence, similar reference numerals will be usedto denote similar components. The main difference between ring 1 and 2is in the annulus-restraining means or annulus-limiting structure, whichin this second embodiment consists of a hoop-and-eyelet arrangement 410.A plurality of eyelets 411 is circumferentially disposed around the baseportion 206 of ring 2, and more specifically, as illustrated, two sucheyelets 411 are attached to each of three U-shaped trough sections 201.A cooperating belt or hoop member 412 is inserted through each of saideyelets, and as such said hoop member 412 is coupled to ring 2. A radialclearance 413 between trough sections 201 and hoop member 412 allowsring 2 to deflect at its base 206 without being affected by hoop member412. Over a predetermined range established by said radial clearance413, the base 206 of ring 2 may undergo radial deflections without beingcontrolled or modulated by hoop member 412 (FIG. 14B). Beyond the limitsof said predetermined range, ring base 206 (and more specifically troughsections 201 thereof) comes into contact with said hoop, and as suchsaid ring base (and aortic root 90,91 attached thereto) is restrained orlimited from further radially outward deflection (FIG. 14C). Hoop 412restrains ring 2 from further outward radial movement, to the extentthat hoop 412 flexibility will allow, based on its design and materialproperties. For example, a very stiff hoop 412 may entirely preventfurther radial outward deflections of ring 2, while an elastic hoop 412will restrain further deflections of ring 2 to the degree that itsradial stiffness will permit. As such, the design of hoop 412 may beoptimized to provide the desired amount of restraint to appropriatelymodulate the base 97 of the aortic root 91 and also limit the maximumdiameter of the native valve annulus 92. Hoop 412 may be fabricated froma metallic, polymeric, or textile material. Eyelet 411 may be configuredas an extension of textile covering 600, or an elastomeric eyeletconfigured as a part of the elastomeric layer 500, or even connected orcoupled to U-shaped frame member 210. The other difference between ring1 and 2 is that, in ring 1, the annulus restraining means in nature oftether 401 spans only across interleaflet zone 204, while in ring 2, theannulus restraining means in nature of hoop-and-eyelet arrangement 410spans across interleaflet zone 204, and also therebeyond.

Referring now more specifically to FIGS. 15A-15B, there is shown aprosthetic aortic annuloplasty ring 3 in accordance with a thirdembodiment of the present invention. Ring 3 is substantially similar toring 1, hence, similar reference numerals will be used to denote similarcomponents. As illustrated, only the portion of ring 3 in proximity toone of the infra-commissure zones 204 is shown. The main difference withring 1 is in the annulus-restraining means or annulus-limitingstructure, which in this third embodiment consists of a hook-in-linkarrangement 420. Said arrangement 420 includes three loop or linkmembers 421, each of which is attached to a different U-shaped troughsection 201 in proximity to ring base 206 of ring 3. Each of said links421 extend circumferentially within their respective infra-commissurezone 204, from trough section 201 to which they are attached towards theadjacent trough section 201. Cooperating with said link members arethree hook members 422. Each of hook members 422 is also attached to aseparate U-shaped trough section 201 of ring 3, and extends from troughsection 201 to which they are attached towards a cooperating link member421 that is attached to an adjacent trough section 201. A tangential orcircumferential clearance 423 between cooperating link 421 and hook 422allows ring 3 to deflect at its ring base 206 without being affected bysaid hook-in-link arrangement 420. Over a predetermined rangeestablished by said circumferential clearance 423, ring base 206 mayundergo radial deflections without being controlled or modulated by saidhook-in-link arrangement (FIG. 15A). Beyond the limits of saidpredetermined range, said hook comes into contact with said link, and assuch the ring base 206 (and aortic root 90,91 attached to ring 3) isrestrained or limited from further radially outward deflection (FIG.15B). Hook 422 may be fabricated from a metallic or polymeric material.Link 421 may be configured as a fabric loop extending from textilecovering 600, or an elastomeric link configured as a part of elastomericsheath 500, or even a metallic or polymeric link connected to framemember 210.

FIGS. 16A-16C schematically illustrate a variant 430 to the hook-in-linkarrangement 420 of ring 3. An elastic component or spring member 431 isintroduced between trough section 201 and hook 422, and adjacent troughsection 201 and link 421. Similar to the embodiment illustrated in FIG.15A, over a predetermined range established by the circumferentialclearance 423, ring base 206 of ring 3 (and three trough sections 201thereof) may undergo radial deflections without being controlled ormodulated by said hook-in-link arrangement 430 (FIGS. 16A and 16B).Beyond the limits of said predetermined range, said hook 422 comes intocontact 432 with said link 421, at which point the spring stiffness ofspring members 431 would come into effect and progressively increase therestraining force exerted by hook-in-link arrangement 430 between twoadjacent trough sections 201.

Referring now to FIG. 17, there is shown a prosthetic aorticannuloplasty ring 4 in accordance with a fourth embodiment of thepresent invention. Ring 4 is substantially similar to ring 1, hence,similar reference numerals will be used to denote similar components. Asillustrated, only a portion of ring 4 in proximity to one of theinfra-commissure zones 204 is shown. The main difference with the firstembodiment is in the annulus-restraining means or annulus-limitingstructure, which in this fourth embodiment consists of a shacklearrangement 440. Six pin members 441 are circumferentially disposedaround the ring base 206 of ring 4. As illustrated, two of the six pins441 are shown, one pin attached to a first trough section 201 andanother pin attached to an adjacent trough section 201. A generallyelongate strap member or shackle 442 is slidingly connected to twoadjacent pins 441 thereby spanning the infra-commissure zone 204therebetween and, as such, also being coupled to ring 4. Each shackle442 is configured with at least one elongate slot or channel 443 withinwhich at least one of said pins 441 is free to slide. As illustrated,shackle 442 is configured with a pair of channels 443, one said channelfor engagement with one of pins 441. A tangential or circumferentialclearance 444 between pin 441 and end of slot 443 allows ring base 206of ring 4 (and more specifically trough section 201 thereof) to deflectsubstantially without being affected by said shackle 442. Over apredetermined range established by said circumferential clearance 444,ring base 206 of ring 4 may undergo radial deflections without beingcontrolled or modulated by shackle 442. Beyond the limits of saidpredetermined range, pin 441 comes into contact with one of theextremities of said shackle slot 443, and as such ring base 206 (andaortic root 90 or 91 attached thereto) is restrained or limited fromfurther radial deflections. Shackle 442 restrains ring 4 from furtherradial movement, to the extent that shackle flexibility will allow basedon its design and material properties. For example, a very stiff shackle442 can entirely prevent further radial outward deflections of ring base206, while an elastic shackle will restrain further deflections of ringbase 206 to the degree that its structural stiffness will permit.Shackle 442 may be fabricated from a metallic, polymeric, or textilematerial. Pin 441 is preferably attached to and protruding from U-shapedframe member 210. Alternatively, shackle 442 may be fixedly attached atone end to frame member 210, and slidingly attached to frame member 210at opposed end through pin 441.

Referring to FIGS. 18A and 18B, there is shown a prosthetic aorticannuloplasty ring 5 in accordance with a fifth embodiment of the presentinvention. Ring 5 is substantially similar to ring 1, hence, similarreference numerals will be used to denote similar components. Asillustrated, only a portion of ring 5 in proximity to one of theinfra-commissure zones 204 is shown. The main difference with the firstembodiment is in the annulus-restraining means or annulus-limitingstructure, which in this fifth embodiment consists of a webbed tetherarrangement 460. In FIG. 18A, fabric covering 600 extends below crestsections 202 (and below end fitting 300), and is draped between twoadjacent U-shaped trough sections 201 to substantially coverinfra-commissure region 204 with a fabric or textile web 461. Saidtextile web 461 is preferably made from pleated or crimped fabric.Textile web 461 may be made of the same material as fabric covering 600and extending therefrom as an integral part thereof, or made as aseparate part from either a similar or different material and assembledto ring structure 5 to form a composite assembly. Textile web 461 may beof a woven or knit construction, or other textile construction thatallows or promotes the function of a tether as described above inreference to the first embodiment.

In a variant of this fifth embodiment, illustrated in FIG. 18B, ring 5is configured with the elastomeric layer or sheath 500 extending belowcrest sections 202 and end fittings 300, and is draped between twoadjacent U-shaped frame members 210 in a manner to substantially coverinfra-commissure zone 204 with an elastomeric web 462. Elastomeric web462 may be of variable thickness along its height, circumferentialwidth, or both, in order to fine-tune the flexibility or elasticity ofsaid web 462 to allow proper modulation or control of dimensions ofaortic root 90 by ring 5. Elastomeric web 462 may also be made from adifferent material than elastomeric sheath 500. Alternatively, web 462may be made as a composite construction having fibre reinforcement atstrategic locations therein to tailor flexibility of said web in certaindirections. Alternatively still, at least a portion of said elastomericweb 462 may also be covered by a textile fabric covering similar totextile fabric used to make web 461.

In reference to FIG. 19A, the three inferior or base portions 208 oftrough sections 201 coupled with the three tether members 401, togetherform a substantially circular ring perimeter 205. Similarly in FIG. 19B,the three base portions 208 coupled with the three textile web members461, together form a substantially circular ring perimeter 205.

Said ring perimeter 205 is schematically illustrated in FIG. 19C whichshows ring 1 in a first ring configuration 280 occurring generallyduring diastole, and in FIG. 19D which shows ring 1 in a second ringconfiguration 290 occurring generally during systole. Also illustratedin FIGS. 19C and 19D, is the effect of tether 401 on ring base 206, andmore specifically inferior or base portions 208 thereof. In FIG. 19C,said tether 401 permits ring base portions 208 to deflect radiallyinward, in a substantially free and unhindered manner, and in compliancewith dynamic aortic root movement during the diastolic phase of cardiaccycle. In FIG. 19D, said tether 401 limits ring base portions 208 todeflect radially outward only a predetermined amount, said amountestablished by the effect of tether 401. As such, the maximum diameterat base 97 of aortic root 91 is restrained by tether 401, typicallyduring the systolic phase of the cardiac cycle. Variations in diameterat base or aortic root are controlled or modulated by tether 401 as ring1 changes configuration between said first 280 and second ringconfigurations 290.

Referring to FIG. 19A, the annulus-restraining means or annulus-limitingstructure in nature of tether 401 results in a fenestrated arrangementwithin the inter-leaflet zone 204, with one aperture 451 createdrespectively between said tether 401 and below crest section 202.Alternatively, rings may be designed with a combination of one or moretethers 401 spanning over said inter-leaflet zone 204 resulting in afenestrated arrangement with a plurality of apertures (not shown).Referring to FIG. 19B, annulus-restraining means or annulus-limitingstructure in nature of web 461 results in a non-fenestrated arrangementwithin the inter-leaflet zone 204.

Referring now to FIG. 20A, ring 1 is illustrated in its non-implantedfree-state configuration 270, that is, in its fabricated configurationfree from exposure to aortic pressure and cardiac muscle contractions.Elements of ring 1 such as annulus-restraining means 400 in nature oftether 401, elastomeric layer or sheath 500, and textile or fabriccovering 600 are not shown in FIGS. 20A-20C to more clearly show theunderlying three peak ring structure or frame 200.

In its free-state configuration 270, ring 1 has a shape that generallyconforms to a truncated cone defined by a half cone angle θ_(f). Ring 1is defined by a diameter D_(BF) at its ring base 206, said diameterD_(BF) being located substantially within plane BASE. At the top 207 ofring 1, said ring is defined by a smaller diameter D_(TF), said smallerdiameter D_(TF) being located substantially within plane TOP. Plane TOPis located at a height H above plane BASE.

In proximity to ring base 206, the three trough sections 201 (and morespecifically three points “b” located thereon) are spaced apart anddefine a diameter D_(BF). In proximity to top 207 of ring 1, the threecrest sections 202 (and points “c” located thereon) are spaced apart anddefine a diameter D_(TF).

When ring 1 is implanted around aortic root 91 and exposed to cardiacmuscle contractions and aortic pressures, it will deflect from its freestate configuration to assume a variety of implanted configurationsbased on the variable or dynamic ring loading imparted from a varyingcardiac cycle. According to the principles of the present invention,ring 1 is by virtue of its design configured and sized to deflectpredetermined calculated amounts under said variable cardiac cycle, andas such assume a variety of advantageous implanted configurations thatwill allow ring 1 to modulate and control key aortic root dimensions. Asa result, normal aortic valve physiology tends to be preserved orrestored, as well as proper leaflet 912 coaptation and blood transportthrough the aortic valve 94.

Referring now to FIGS. 20B and 20C, two such advantageous implanted ringconfigurations are described in greater detail. FIG. 20B illustratesprosthetic ring 1 in an implanted first ring configuration 280, saidfirst ring configuration occurring at a time interval during thediastolic phase of the cardiac cycle. In said first diastolicconfiguration, ring 1 still assumes a truncated cone or substantiallyconical shape, but the half cone angle θ_(DIAS) is smaller than θ_(f).Due largely to muscle contraction, the base diameter D_(BD) is drawnradially inward relative to free state diameter D_(BF), such radiallyinward ring deflection 281 being allowed to occur, substantially withoutrestraint, by the design of tether member 401. Due to the aorticpressure loading now acting on ring 1 when said ring is exposed to thediastolic phase in the cardiac cycle, crest sections 202 are drawn apartrelative to their free state configuration, to define a larger topdiameter D_(TD). Ring 1 is designed such that under diastolic pressureloading, crest sections 202 move apart relative to their free stateconfiguration, but only to a predetermined extent that promotes propervalve leaflet coaptation.

FIG. 20C illustrates prosthetic ring 1 in an implanted second ringconfiguration 290 occurring at a time interval during the systolic phaseof the cardiac cycle. In said second systolic configuration, ring 1assumes a substantially cylindrical shape, with the half cone angleθ_(SYST) approaching zero. Due largely to heart muscle contraction atthe onset of systole being overtaken by the resulting increase inventricular and aortic pressure, the base diameter D_(BS) is drawnradially outward relative to first diastolic diameter D_(BD), suchradially outward ring deflection 291 being permitted, regulated, andlimited to a predetermined maximum by the design of tether member 401.Due to the increased aortic pressure loading now acting on ring 1 whensaid ring is exposed to the systolic phase in the cardiac cycle, crestsections 202 are drawn apart relative to their diastolic configuration,to define a larger top diameter D_(TS). Ring 1 is designed in such amanner that under systolic conditions, trough sections 201 (and morespecifically base portions 208 thereof) move apart to a predeterminedmaximum as governed or controlled by tether 401, and crest sections 202move further apart relative to their diastolic configuration, but onlyto the predetermined extent that allows desired leaflet triangulationgenerally without overstressing of said leaflets.

According to the present invention, ring 1 is movable between a firstdiastolic configuration 280 where it assumes a substantially conicalshape and a second systolic configuration 290 when it assumes asubstantially cylindrical shape, the diameter at ring base 206increasing in size from said diastolic to said systolic configurationand the diameter at ring top 207 increasing in size from said diastolicto said systolic configuration. Variants of ring 1 are possible withoutdeparting from the spirit of the invention. For instance, the diameterat base 206 of ring 1 may alternatively be designed to change verylittle, or remain substantially unchanged between the diastolic andsystolic configuration, while only the diameter at top 207 increases insize between said diastolic and systolic configuration.

In a specific example of an embodiment according to the principles ofthe present invention, ring 1 may have the following dimensions in itsfree state configuration 270: D_(BF)=28 mm; H=19 mm; D_(TF)=14 mm;θ_(f)=approx 20 degrees. In a diastolic configuration 280, the followingdimensions: D_(BD)=25.5 mm; D_(TD)=18.8 mm; θ_(DIAS)=approx 10 degrees.In a systolic configuration 290, the following dimensions: D_(BS)=31 mm;D_(Ts)=29.2; θ_(SYST)=approx 2.5 degrees.

It should be understood that this above example is just one specificexample of a ring 1 embodiment, whose dimensions are determined in largepart by the material properties of the ring components, and associateddesign of said ring components using said material properties. Differentmaterials or designs may result in a ring geometry with differentdimensions to the above example. For example, a second ring may bedesigned with a larger free state base diameter D_(BF), but said secondring may still be designed to assume the same desired base diameterD_(BS) in systolic configuration 290 as the first ring 1 in the aboveexample. As such, this second ring will have a smaller deflection rangebetween its free state configuration 270 and its systolic configuration290, but a corresponding larger deflection range between its free stateconfiguration 270 and its diastolic configuration 280.

Many other examples of prosthetic rings 1 may be designed withoutdeparting from the spirit of the present invention. Such other rings mayhave dimensions generally within the following range: θ_(f)=10-20degrees; H=0.6 D_(BF) to 1.1 D_(BF); θ_(DIAS)=5-15 degrees; θ_(SYST)=−5to +5 degrees. In another example still, prosthetic ring 1 may have thefollowing dimensions in its free state configuration 270: D_(BF)=30 mm;H=21 mm; D_(TF)=15 mm; θ_(f)=approx 20 degrees. In a diastolicconfiguration 280, the following dimensions: D_(BD)=31.5 mm; D_(TD)=26mm; θ_(DIAS)=approx 7 degrees. In a systolic configuration 290, thefollowing dimensions: D_(BS)=30.8 mm; D_(Ts)=30 mm; θ_(SYST)=approx 1degree.

The range of H described above allows points “c” on ring 1 (and morespecifically on crest sections 202 thereof) to be located either belowpoints “C” on commissures 96, in register or close proximity to points“C”, or above points “C”. In the preferred embodiment of ring 1, H ispreferably approximately 0.7-0.9 times the diameter of ring base 206 sothat ring crest sections 202 are in general proximity to valvecommissures 96. Variants of ring 1 may be configured with a variety ofdifferent heights H, for a given diameter of ring base 206, provided theproper ratio of top diameter 207 as a function of such varying height His respected. For example, the greater the height H of a ring 1 for agiven base diameter, the smaller the ratio of top diameter to basediameter of ring, and the greater the range of radial deflection orexcursion of crest section 202 during the cardiac cycle, in order topromote adequate leaflet 912 coaptation during diastole, and desiredtriangulation of leaflets during systole to promote efficient bloodtransport through aortic valve 94. For a given base 206 diameter of ring1, a greater ring height H may also have an impact on the placement ofring fixation sutures or method of attachment of ring 1 to aortic root91.

Rings 1 with a preferred range of dimensions will lie in close proximityto valve annulus 92, and fixation sutures will tend to be placed frombelow valve leaflet 912 through said valve annulus, and subsequentlythrough a portion of ring 1 in a manner to secure said ring to aorticroot 91. In a ring 1 having a greater height H to ring base 206 diameterratio, the base or inferior portion 208 or trough section 201 will stilltend to be in close proximity to valve annulus 92 and allow fixationsutures to be placed below leaflet 912 in order to pierce said valveannulus and subsequently ring 1. However, in such higher rings, in partsof ring 1 approaching top 207 of said ring, such as crest section 202,fixation sutures may have to be placed above leaflet 912 in order topierce through annulus 92 and subsequently through said higher lyingring portions. This is especially true when top 207 of ring 1 extendsabove the plane containing valve commissures 96.

For a given patient, the size of ring 1 to be implanted may beadvantageously selected as a function of the native leaflet size andcorresponding diastolic diameter required for adequate leaflet coaption,and extrapolating from such diastolic diameter the maximum ring basediameter required to properly resize a dilated aortic root or valveannulus.

Asymmetric variants of ring 1 may also be advantageously configured tocater for patients having unequally-sized native valve leaflets. Forexample, a variant asymmetric ring 1 may be configured with one or allof the three U-shaped trough sections 201 being of a different size. Assuch, the circumferential distance between adjacent crest sections 202will be different. Alternatively still, ring 1 may be configured withone or all of crest sections 202 extending a different height aboveplane BASE, and one or all of trough sections 201 extending below baseplane BASE.

Referring now to FIG. 21A, in a graphical representation 260 areillustrated the varying dimensions of a dynamic aortic root 90 as afunction of the different phases of the cardiac cycle. Left verticalaxis 261 of graph 260 plots the effective diameter of aortic root as apercentage change relative to a baseline diameter, said baselinediameter arbitrarily selected as the aortic root diameter at 100 mmHg ofblood pressure. Right vertical axis 262 plots the blood pressure withinthe aortic root 90. Horizontal axis 263 plots time during the cardiaccycle, and in particular time points 21B, 21C, 21D occurring during thesystolic phase, and time points 21E, 21F, 21G occurring during thediastolic phase. Although time point 21B to 21G are equally spaced alongtime axis 263, the time elapsed between two adjacent time points is notequal in duration. Plot 264 illustrates the variation in base diameter97 of said aortic root as a function of time in the cardiac cycle, whileplot 265 illustrates the variation in the top diameter of said aorticroot, generally at the level of commissures 96. Plot 266 illustrates thevariations in blood pressure within the aorta. FIG. 21A is based on datafrom a review of the medical literature focusing on aortic rootdynamics, and diagrammatically illustrates a simplified interpretationof said data. Inclusion of new data or exclusion of some data may alsoalter the shape of the graphical plots in graph 260. As illustrated, thebase diameter 97 and top diameter at level of commissures 96 vary +/−10degrees relative to their baseline diameters.

FIGS. 21B-21G schematically represent a range of varying implanted ringconfigurations that ring 1 may assume during the different phases of thecardiac cycle. More specifically, FIGS. 21B, 21C, and 21D illustratevariations in ring 1 configuration occurring at three time points 21B,21C, 21D occurring during the systolic phase, and FIGS. 21E, 21F, 21Goccurring at three time points during the diastolic phase. In FIGS.21B-21G, dashed line 267 represents a reference baseline diameter forring 1, dotted line 268 represents a minimum diameter reference,typically inferior to baseline diameter by 10%, and dotted line 269represents a maximum diameter reference, typically superior to baselinediameter by 10%. Not all of said lines are visible in each of saidfigures. As illustrated in FIG. 21F, ring 1 assumes a first diastolicconfiguration 280 with ring base 206 having a diameter of −5% relativeto baseline 267, and ring top 207 having a diameter −10% relative tobaseline 267. Said base and top diameters will vary with cardiac cycleand, as illustrated in FIG. 21C, ring 1 assumes a second systolicconfiguration 290 with ring base 206 and ring top 207 both having adiameter of +10% relative to baseline 267. Between said first and secondconfigurations, ring 1 will vary in shape between a substantiallyconical shape at time point 21F and a substantially cylindrical shape attime point 21C.

Ring deflections at the top 207 of ring 1 are influenced in large partby the pressures within the aorta. Ring deflections at the base 206 ofring 1 are influenced mostly by muscle contractions and relaxationsduring the cardiac cycle, and are governed by the effect ofannulus-restraining member or tether 401 which also sets a limit on themaximum base deflections and base diameter that ring 1 will be capableof assuming. Since the crest sections 202 of the ring 1 extend from thering base 206, ring deflections at the base 206 also play a role ininfluencing ring deflections at the top 207 of ring 1. A prosthetic ring1 according to the present invention is based on these and other designconsiderations to obtain the predetermined desired ring deflections. Itis also understood that changing plots 261, 262 (either by design or toreflect alternate ways of interpreting the medical data) may result in aring having different properties than the example illustrated in FIGS.21B to 21G, and such a ring may have different changes in dimensionsrelative to baseline diameter 267.

Referring now more specifically to FIG. 22A, there is shown a compositeprosthetic ring-conduit 6 in accordance with a sixth embodiment of thepresent invention. The embodiment 6 includes a prosthetic ring 8,substantially similar to any of the previously described prosthetic ringembodiments 1, 2, 3, 4, 5 and also includes a prosthetic conduit 7 thatis advantageously attached to said ring 8 to form a compositering-conduit 6 assembly.

Prosthetic conduit 7 is comprised of two sections or lengths of crimpedfabric or textile, such as Dacron, or other biocompatible fabricsavailable with pleats and appropriate for implant use. A first conduitlength or portion 71 is configured with pleats 711 in an axially stackedarrangement to allow stretch or substantially elastic expansion in anaxial direction 713, thereby allowing said first conduit portion 71 tovary in length along said direction 713. As with commercially availableconduits having axially-stacked pleats, the conduit is stretchable orexpansible in an axial direction, but substantially non-elastic ornon-expansible in the radial direction. A second conduit length orportion 72 is configured with pleats 721 in a circumferentially stackedarrangement to allow stretch of substantially elastic expansion in acircumferential direction 723, thereby allowing second conduit portion72 to vary in diameter. As such, second conduit portion 72 issubstantially non-expansible in the axial direction.

Conduit portion 72 is provided with sufficient pleating to permit ring 8to expand or radially deflect within its plane TOP, and morespecifically at points “c” thereon, according to the principles of thepresent invention as having been already described above in reference toFIGS. 19-21. Said sufficient pleating will permit ring 8 to assume itsmaximum ring diameter within plane TOP, substantially without anyrestraint being applied by said conduit portion 72 thereon.

The amount of expansion or contraction that conduit portion 72 (andpleats 721 thereof) will experience in proximity to the base plane BASEof ring 8 will be determined and controlled by the deflections of ringbase 206 as governed by the effect of tether 401. That is, ring 8 willoutwardly deflect or expand to assume a larger ring base diameter to thelimit permitted by tether 401, while pleats 712 simultaneously unfold toallow said outward deflection substantially without hindrance orrestraint thereon. Said expansion of ring 8 is being governed by therestraining or limiting effect of said tether and not by pleats 721 inconduit 72. Inward deflections or contractions of ring 8 may occursubstantially freely since pleats 721 will adequately generally complywith ring deflections in a radially inward direction.

At conduit junction 722 between conduit portion 71 and 72, the axiallystacked pleat 711 inhibits the radial expansion of circumferentiallystacked pleats 721 of conduit portion 72. As such, length L of conduitportion 72 must be sufficiently long so that length G between TOP ofring 8 and conduit junction 722 provides sufficient allowance for points“c” on ring 8 to deflect radially, without being hindered or restrainedby conduit portion 72 (or pleats 721 thereof). Typically, length G isapproximately between 25% and 50% of length L. The stretch alongdirection 713 available in conduit portion 71 will allow for changes inlength L that may result when points “c” deflect radially outward withthe expansion of ring 8.

Circumferential pleats 721 also advantageously allow the creation ofpseudo-sinuses of Valsalva 724, since conduit portion 72 is free tobulge outward in cusp region 203 from the effect of aortic pressuretherewithin, and the unfolding of circumferentially stacked pleats 721.This bulging occurs even when ring 8 is in its first or diastolicconfiguration 280, and native valve leaflets 912 are coapting. As such,the normal physiology of aortic valve 94 tends to be preserved orrestored.

Referring now more specifically to FIG. 22B, there is shown a variantcomposite prosthetic ring-conduit 60. Variant ring-conduit 60 isdifferent to the ring-conduit 6 (FIG. 22A) in that it includes a variantprosthetic conduit 73, said conduit 73 however is still advantageouslyattached to ring 8 to form a composite ring-conduit assembly. Conduit 73is similar in construction to a traditional aortic graft prosthesis withaxially-stacked pleats 731. The diameter 732 of the conduit 73 isoversized relative to the aortic root base 97 diameter or valve annulus92 diameter. Diameter 732 is also oversized relative to the maximumdiameter that ring base 206 of ring 8 will assume during the differentphases of the cardiac cycle. As such, oversized conduit 73 provides thematerial allowance to permit ring 8 to radially deflect or expandaccording to the principles of the present invention, said ringdeflections being substantially unhindered by said oversized conduit. Inaccordance with the principles of the present invention, the maximumring deflections at ring base 206 are governed or limited by the effectof tether 401. As such, ring 8 controls or modulates the dimensions ofaortic root 91 (and also valve annulus 92 therewithin), independentlyfrom oversized conduit 73.

As a further variant to the composite prosthetic ring-conduit shown inFIGS. 22A and 22B, the pleated or crimped Dacron used for the conduitconstruction may be replaced by other similar biocompatible materialssuitable for implant use and which allow for elastic expansion in one ormore directions.

Referring now more specifically to FIG. 22C, there is shown a variantcomposite prosthetic ring-conduit 61 to the sixth embodiment illustratedin FIG. 22A. Variant ring-conduit 61 is different to the ring-conduit 6in that it includes a variant prosthetic conduit 74, said conduit 74however is still advantageously attached or integral with ring 81 toform a composite ring-conduit assembly 61. Conduit 74 is constructedfrom a substantially elastic biomaterial such as a hydrogel, or anyother like elastic biomaterial suitable for implant use and for contactwith blood. More specifically, conduit 74 is preferably constructed froma cryogel polyvinyl alcohol (cPVA) having been cross-linked by repeatfreeze-thaw cycles to obtain the desired elasticity, similar to nativeaortic root tissue. Typically, three to five such freeze-thaw cycles maybe employed to construct a cPVA biomaterial with the desiredrepresentative material properties. Ring 81 is preferably introducedwithin a mold, having the negative cavity shape of the cPVA conduit 74,that is to used to fabricate said conduit. As such, ring 81 may becoated or overmolded by cPVA material during the fabrication of saidconduit 74, and is advantageously embedded within conduit 74 (ring 81illustrated in dashed line). Ring 81 is similar to prosthetic ringsdescribed in previous embodiments of ring 1 but may not include all thefeatures of said rings. Ring 81 will include at least a scallopedthree-peak ring structure 200 and a tether 401 similar to those ofprevious embodiments. Alternatively, conduit 74 may be producedindependently and subsequently attached to ring 81 to produce acomposite prosthetic ring-conduit 61. Conduit 74 may preferably includea bulging section 75 at each of the cusp zones 203 to more closelysimulate the sinuses of Valsalva in native aortic root 90. Bulgingsection 75 may be designed to have thinner wall thicknesses that theascending aorta section 76, since radial deflections of the conduitwithin this section 75 will be substantially governed by the ring 81according to the principles of the present invention as described inreference to FIGS. 19-21. A conduit 74 that is fabricated from a cPVAmaterial, or other like biomaterial, is substantially elastic in anaxial direction 751 and radial direction 752. Optionally, fibrereinforcements may be introduced in the cPVA material during thefabrication process to tailor material properties to desired stiffnessalong a desired conduit direction. Optionally, the cPVA material may beproduced with different number of freeze-thaw cycles at differentlocations within conduit 74. As such, the material properties may betailored at different conduit locations as a function of the number offreeze-thaw cycles. Alternatively, hydrogels that are cross-linked by avariety of methods (i.e. light, chemical, radiofrequency, etc.) may alsobe used instead of cPVA, provided such hydrogels are biocompatible,suitable for implant use in a blood-contacting environment, andpreferably impervious to blood. Other examples of suitable conduitmaterials include polyurethane, polyetherurethaneurea,poly(carbonate)urethane, and other like materials or derivativesthereof.

The embodiments described and illustrated in FIGS. 22A-22C arepreferably surgically implanted over a resected and scalloped aorticroot 91 as shown in FIG. 3A. The embodiments described and illustratedin FIGS. 22A-22C provide a one-piece aortic root prosthesis that mayadvantageously be implanted as a single implantable structure 6, 60, 61,said implantable structure consisting of a prosthetic ring 8, 81 and anassociated aortic conduit 7, 73, 74. Such a single structure 6, 60, 61further facilitates an aortic valve-sparing procedure, or aortic rootreconstruction, relative to a two-piece arrangement consisting of aseparate prosthetic ring 1 and a separate independent aortic conduitbeing connected in-situ during said surgical procedure.

Referring now more specifically to FIGS. 23A-23C, there is shown ademountable prosthetic ring 9 in accordance with a seventh embodiment ofthe present invention. Ring 9 has a number of substantially similarfeatures or components to ring 1, hence, similar reference numerals willbe used to denote similar components. The main difference between rings1 and 9 is that ring 9 is designed and configured to be deployed in avalve-sparing procedure, or aortic root reconstruction, avoiding theneed to incise the aorta AA in order to allow placement of said ring 9therearound.

As illustrated in FIGS. 23A-23C, some of the features or components thatring 9 has in common with ring 1 have not been shown in order to betterillustrate the differences relative to ring 9. For instance, elastomericsheath 500 and textile covering 600 have not been shown, but may beincluded as components of ring 9.

Ring 9 is comprised of three U-shaped frame members 210. At two of thethree crest sections 202, two adjacent frame members 210 are connectedby an end fitting 300, in a similar manner to previously described ring1. At the remaining one of three crest sections 202, a two-pieceassemblable end fitting 390 is used to close and complete said thirdcrest section. End fitting 390 is comprised of two mating fittings 391,392. Each of said mating fittings 391, 392 is attached to one of tworemaining adjacent posts 212, in a similar manner as end fitting 300 isattached to posts 212. Fitting 391 is configured with pins 393 toprovide a mating snap-fit engagement with cooperating holes 394 inmating fitting 392. Through engagement of mating fittings 391, 392,prosthetic ring 9 may assume a closed ring configuration 295 asillustrated in FIG. 23B, said closed ring configuration 295 beingsimilar to ring 1. Variants to the pin-in-hole mechanical connection arepossible such as tongue-in-groove, or any other mechanical connectionthat provides quick, reliable, assemblable connection of mating fittings391,392.

Proximal to base 206 of ring 9, each of said three frame members 210 iscoupled to the other two adjacent members 210 by an annulus-limitingmeans or annulus-restraining member in the nature of brace or tiemembers 490, 495. Brace member 495 is demountably coupled to one offrame members 210, such that when said mating fittings 391, 392 are notconnected and brace member 495 is uncoupled to member 210, ring 9 mayassume an open ring configuration 296 as illustrated in FIG. 23C. Insaid open configuration, mating fittings 391, 392 may be sufficientlyspaced apart by a gap 399 to allow ring 9 to be assembled around aorticroot 90 without having to incise aorta AA. This is particularlyadvantageous since avoiding an aortotomy incision may also avoid placingthe patient on extracorporeal circulation during the surgical procedure.

Three hinge-type pin members 492 and three translating pins 491 arecircumferentially disposed around the base 206 of ring 9. Twotranslating pins 491 are attached to trough section 201 of one of theU-shaped frame members 210; two hinge pins 492 are attached to anotherone of the U-shaped members 210; and one of each pins 491, 492 areattached to the remaining one of the U-shaped members 210. Threegenerally elongate brace members 490, 495 are each pivotingly engaged orconnected to one of said hinge pins 492. Brace members 490 are alsoslidingly engaged with a respective one of said translating pins 491through a generally elongate slot 493 configured in said brace member490, such sliding engagement being non-demountable. Conversely, bracemember 495 is slidingly engaged with translating pin 491 through slot497, with said sliding engagement being demountable through accessgroove 496.

In the assembled closed ring configuration 295 (FIG. 23B) said bracemembers 490, 495 span the infra-commissure zone 204, and translating pin491 is located in its generally distal-most position relative tohinge-pin 492. A tangential or circumferential clearance 499 between pin491 and terminal end 498 of slot 493 allows ring 9 to deflect at itsbase 206 without being affected by brace 490, 495. Over a predeterminedrange established by said circumferential clearance, said base of ring 9can undergo radial deflections without being controlled or modulated bybrace 490,495. Beyond the limits of said predetermined range, pin 491comes into contact with one of the extremities of said slot 493, 497 andas such the ring base 206 (and aortic root 90 attached thereto) isrestrained or limited from further radial deflections. Braces 490, 495restrain ring 9 from further radially outward movement, to the extentthat brace flexibility will allow, contingent on the design and materialof said brace. For example, a very stiff brace can entirely preventfurther radially outward deflections, while an elastic brace willrestrain further deflections to the degree that its structural stiffnesswill permit. Brace 490, 495 may be fabricated from a metallic, orpolymeric material. Pins 491, 492 are preferably attached to, andprotruding from, frame member 210.

With mating fittings 391, 392 not connected, and with brace 495decoupled from pin 491, ring 9 may be folded or collapsed to assume acompact, collapsed configuration 294 as illustrated in FIG. 23A.Pivoting of brace members 490, 495 about hinge pin 492 will urge pins491 to translate along slot 493 toward pins 492. In the limit condition,when said pins 491 are in general proximity to hinge pins 492, ring 9 isin its most compact configuration with brace members 490, 495 beingsubstantially aligned with posts 212. Such a compact arrangement 294allows ring 9 to be advantageously deployed through an endoscopic orintercostal port-access surgical approach. As such, a classic sternotomyincision may be avoided.

FIGS. 24A-24D illustrate a variety of suturing arrangements and methodsin which a prosthetic ring 1, 2, 3, 4, 5 may be implanted on a resectedaortic root 91, and affixed to a vascular conduit 95.

FIG. 24A illustrates a suturing arrangement including two suture lines901 and 902. In this arrangement, fringe 910 of aortic root tissue liesoutboard relative to vascular conduit 95. Suture 901 is placed aboveleaflet 912 and attaches fringe 910 to conduit 95. Suture 902 is placedbelow the leaflet 912, through the native valve annulus 92 and throughprosthetic ring 1.

FIG. 24B illustrates a suturing arrangement including one suture line903 having two surgical needles 904 (double armed). In this arrangement,fringe 910 also lies outboard relative to vascular conduit 95. One endof suture 903 is placed from above leaflet 912, through valve annulus 92and through prosthetic ring 1. The opposed end of suture 903 is placedthrough vascular conduit 95 and through fringe 910. The two ends ofsuture 903 are then tied outside the aorta.

FIG. 24C illustrates a suturing arrangement including one suture line903 having two surgical needles 904 (double armed). In this arrangement,fringe 910 of aortic root tissue lies inboard relative to vascularconduit 95. One end of suture 903 is placed from above leaflet 912,through valve annulus 92 and through prosthetic ring 1. The opposed endof suture 903 is placed through fringe 910 and vascular conduit 95. Thetwo ends of suture 903 are then tied outside the aorta.

FIG. 24D illustrates a suturing arrangement including one suture line903 having two surgical needles 904 (double armed). In this arrangement,fringe 910 of aortic root tissue lies inboard relative to vascularconduit 95. One end of suture 903 is placed from below leaflet 912,through valve annulus 92 and through prosthetic ring 1. The opposed endof suture 903 is also placed from below leaflet through valve annulus 92through fringe 910 and through vascular conduit 95. The two ends ofsuture 903 are then tied outside the aorta.

FIGS. 25A-25B illustrate a variety of suturing arrangements and methodin which a composite prosthetic ring-conduit 6, 60, or 61 may beimplanted on and affixed to a resected aortic root 91.

FIG. 25A illustrates a suturing arrangement including one suture line905 having one surgical needle 906. In this arrangement, fringe 910 liesinboard relative to conduit section 72, 73 or 75. One end of suture 905is placed from below leaflet 912, through valve annulus 92 and throughprosthetic ring 8, 81. The same end of suture 905 is then returnedthrough ring 8, 81 and through valve annulus 92. The two ends of suture905 are then tied inside the aorta. Alternatively, one end of adouble-armed suture is placed from below leaflet 912, through valveannulus 92 and through prosthetic ring 8, 81. The other end ofdouble-armed suture is also is placed from below leaflet 912, throughvalve annulus 92 and through prosthetic ring 8, 81 to create a U-stitch.The two ends of double-armed suture are then tied outside the aorta.

FIG. 25B illustrates a suturing arrangement including one suture line905 having one surgical needle 906. In this arrangement, fringe 910 alsolies inboard relative to conduit section 72, 73 or 75. One end of suture905 is placed from above leaflet 912, through valve annulus 92 andthrough prosthetic ring 8, 81. The same end of suture 905 is thenreturned through ring 8, 81 and through fringe 910. The two ends ofsuture 905 are then tied inside the aorta.

In valve-sparing surgeries that do not involve resection of the aorticroot to remove aneurysmal tissue, the suturing methods described abovecan be revised to exclude placement of sutures through the syntheticvascular conduit.

In association with the suturing methods for fixation of said prostheticrings to said aortic root, various tether configurations mayadvantageously allow for the placement of ring positioning guide suturestherethrough to aid the surgeon in proper placement and anchoring ofring 1 relative to scalloped aortic root 91, or native aortic root 90.

Other suturing arrangements consisting of a combination of one or moreof the above-described arrangements are also possible.

In the foregoing descriptions of the various ring embodiments, it isunderstood that a scalloped aortic root 91 and native aortic root 90 maybe used interchangeably, depending on whether or not the valve sparingprocedure involves resection of aortic tissue. The various ringembodiments are generally attached to a scalloped aortic root 91 whenresection of aortic tissue is required, such as to remove aneurysmalaortic tissue. In such valve-sparing procedures, the use of a vascularconduit 95 (or ring-conduit 6, 60, 61) is also required to replace saidresected aneurysmal tissue. In valve-sparing procedures that do notinvolve resection of a portion of the aorta or aortic root tissue, suchas those procedures that treat aortic insufficiency or annulo-ectasiawithout aneurysm of the aortic root, the various ring embodiments areattached to a native aortic root 90 and the use of a vascular conduit 95is generally not required.

In the foregoing descriptions of the various ring embodiments, when saidring or aortic root assumes a shape that is not perfectly circular in agiven plane thereof, it is understood that references to the term“diameter”, shall also mean changes to the perimeter of said ring oraortic root in said given plane, or changes to the area contained withinsaid perimeter in said given plane.

In surgical procedures that make use of a vascular conduit 95, thevarious ring embodiments may first be attached to scalloped aortic root91, and said vascular conduit subsequently attached, in situ, to connectthe scalloped aortic root-ring interface to the native ascending aortaAA. Alternatively, vascular conduit 95 may be first be attached to thescalloped aortic root 91 and the various ring embodiments subsequentlyattached to aortic root 91, in situ, before closure of the aortotomyincision between said vascular conduit 95 and ascending aorta AA.

A surgical method associated with the implant of ring 1 may include thefollowing steps:

i. Resect aortic root above leaflet to leave scalloped fringe 910 (FIG.3A);

ii. Assess condition and size of leaflets 912 to determine size of valveannulus required to correct aortic insufficiency and restore properleaflet coaptation;

iii. Select appropriate size of ring 1 that will adequately resizedilated aortic root to ensure leaflet coaptation during diastole;

iv. Preferably, place three U-stitch sutures through each ofinter-leaflet triangle 98 of aortic root 91 and correspondinginfra-commissure zone 204 of ring 1 (preferably through tether 401), toserve as gross positioning sutures for ring 1;

v. Place an adequate number of ring fixation sutures (preferablyU-stitches) through valve annulus 92 and U-shaped section 201 or crestsection 202 of ring 1, for example one suture at each inferior mostlocation 208 of trough section 201, and one suture through each of crestsections 202;

vi. Descend ring 1 onto scalloped aortic root 91 by sliding said ringover suture lines placed through ring 1 and aortic root 91;

vii. Assess leaflet coaptation in aortic root resized by ring 1;

viii. If leaflet coaptation is satisfactory, tie loose suture ends tosecurely fix ring 1 to aortic root 91;

ix. Tailor and fashion a tubular aortic conduit 95 with appropriatelysized and configured scallops so that said conduit scallops approximatescallops of aortic fringe 910 and/or scallops or ring structure 200;

x. Suture conduit 95 to fringe 910 and/or ring 1 and to ascending aortaAA to re-establish blood flow.

In the event that a composite prosthetic ring-conduit 6, 60, or 61 isused, step ix is avoided, and step x is revised to include only suturingof ring-conduit 6, 60, or 61 to ascending aorta AA.

1. An prosthetic device for replacing a portion of a patient's ascendingaorta located adjacent to an aortic root, said aortic root including anaortic valve therewithin, said aortic root and aortic valve beingexposed to alternating diastolic and systolic phases of a cardiac cycle,said prosthetic device comprising: an aortic conduit, said conduit beingsubstantially tubular and extending in length along a longitudinaldevice axis between a first conduit end and a second conduit end, saidfirst conduit end configured and sized for implantation adjacent to saidaortic root; and an annuloplasty ring, said annuloplasty ring coupled tosaid aortic conduit, said annuloplasty ring having an annular baseportion forming a closed perimeter structure adjacent said conduit firstend, said annular base portion including an annulus-restraining member,said annular base portion defining a first diameter and constructed toallow radially inward movement toward said device axis to define asecond diameter smaller than said first diameter, said annulusrestraining member decreasing in circumferential length during saidradially inward movement; whereby, in use, said radially inward movementoccurs during a transition from the systolic phase to the diastolicphase of the cardiac cycle, said prosthetic device constraining theaortic root to a maximum dimension during the systolic phase of thecardiac cycle, and said prosthetic device urging coaptation of theaortic valve during the diastolic phase of the cardiac cycle by allowingsubstantially unhindered inward movement of the aortic root toward saiddevice axis.
 2. The prosthetic device of claim 1 wherein saidannuloplasty ring further includes a plurality of upstanding postsections, said upstanding post sections each having a first and secondpost end, said post sections extending away from said annular baseportion in a direction generally along said device axis and toward saidsecond conduit end to terminate at said second post end, said secondpost ends adapted to move outwardly away from said device axis during atransition from the diastolic phase to the systolic phase of the cardiaccycle, and adapted to retract inwardly toward said device axis during atransition from the systolic phase to the diastolic phase of the cardiaccycle during use of the device.
 3. The prosthetic device of claim 2wherein said conduit is attached to said annuloplasty ring at saidsecond post ends, said conduit attached portions being held by saidsecond post ends closer to said device axis than unattached conduitportions located circumferentially between said upstanding postsections, said unattached conduit portions free to bulge outwardly awayfrom said device axis to form a plurality of conduit bulging sections insaid conduit during the diastolic phase of the cardiac cycle, saidconduit attached portions moving away from said device axis togetherwith said second post ends during a transition from the diastolic phaseto the systolic phase of the cardiac cycle.
 4. The prosthetic device ofclaim 3 wherein when said aortic root is exposed to the diastolic phaseof the cardiac cycle, said post sections and said annular base portionassume a substantially conical shape in which said second post ends arein an approximated spatial relationship relative to each other and tosaid device axis when viewed in a direction along the device axis, saidconical shape transitioning to a substantially cylindrical shape whensaid aortic root is exposed to the systolic phase of the cardiac cyclein which said second post ends are spaced farther apart from each otherand from said device axis relative to said approximated spatialrelationship.
 5. The prosthetic device of claim 2 wherein said aorticconduit is constructed with axially stacked pleats over a first conduitportion spanning between said second conduit end and proximate to saidring second post ends.
 6. The prosthetic device of claim 5 wherein saidaortic conduit is constructed with circumferentially stacked pleats overa second conduit portion spanning between said conduit first end andsaid ring second post ends.
 7. The prosthetic device of claim 1 whereinsaid aortic conduit is constructed from an elastic material suitable forimplant use, and said annuloplasty ring is embedded within said aorticconduit during the fabrication thereof to form an integral assemblytherewith.
 8. The prosthetic device of claim 1, wherein said aorticconduit further comprises a conduit portion between the first and secondconduit ends and, during the diastolic phase of the cardiac cycle, saidconduit portion is configured to bulge radially outward relative to saiddevice axis.
 9. A prosthetic device for replacing a portion of apatient's ascending aorta located adjacent to an aortic root, saidaortic root defining a scalloped valve annulus, said valve annulusserving as attachment for three semilunar valve cusps within said aorticroot, said aortic root spanning in height between a root base portionlocated in general proximity to a left ventricular outflow tract and aroot sinotubular portion located in general proximity to a sinotubularjunction, said valve cusps collectively defining three commissures atthe junction of each of two adjacent cusps in proximity to said valveannulus, said prosthetic device comprising: an aortic conduit, saidconduit being substantially tubular and extending in length along alongitudinal device axis between a first conduit end and a secondconduit end; a space frame, said space frame connected to said aorticconduit adjacent said conduit first end, said space frame including aframe base portion and a frame upper portion spaced from the frame baseportion, said space frame having a scalloped profile defining threetrough sections at said frame base portion and three crest sectionsextending to said frame upper portion arranged circumferentially aroundsaid device axis, said space frame defining a first diameter proximatesaid frame base portion, said space frame constructed to allowcircumferential movement of said trough sections closer to one anothersuch that said space frame defines a second diameter proximate said baseportion, said second diameter being smaller than said first diameter;said prosthetic device configured and sized for placement external tosaid aortic root so as to: 1) generally align said trough sections ofsaid space frame with said valve annulus at said root base portion, 2)generally align said crest sections of said space frame with said valveannulus in proximity to said commissures, and 3) provide a conduitreplacing said portion of the patient's ascending aorta downstream ofsaid aortic root; and an annulus-restraining member, saidannulus-restraining member extending across at least one of said crestportions and generally proximate said frame base portion, and couplingat least two of said trough sections that are adjacent to each other;said space frame movable between a first device configuration and asecond device configuration, in said first device configuration saidspace frame assumes a substantially conical shape in which said crestsections are spaced closer to said device axis than said troughsections, and in said second device configuration said space frameassumes a substantially cylindrical shape in which said crest and troughsections are spaced generally equally away from said device axis;whereby when said space frame is in said second device configurationsaid annulus-restraining member restrains the aortic root to a maximumdimension, and when said device is transitioning between said second andfirst device configurations the construction of said annulus-restrainingmember allows substantially unhindered movement of said trough sectionstoward said device axis in proximity to the root base portion, thesubstantially unhindered movement also resulting in the circumferentialmovement of said trough sections closer to one another thereby allowingsaid device to regulate the dimension of said aortic root.
 10. Theprosthetic device of claim 9, wherein said aortic conduit furthercomprises respective conduit portions between adjacent crest sectionsand, during the diastolic phase of the cardiac cycle, said conduitportions are configured to bulge radially outward relative to saiddevice axis.
 11. A prosthetic device for the surgical repair of anaortic valve of a patient, the aortic valve defining a valve axis andcontained within a generally tubular aortic root, the aortic rootextending in height along the valve axis between a root base portionlocated in proximity to a left ventricular outflow tract and a spacedaway root sinotubular portion located in proximity to a sinotubularjunction, the aortic valve attached to the aortic root through ascalloped valve annulus extending circumferentially around the valveaxis, the aortic valve including a plurality of valve leaflets connectedto the valve annulus, the leaflets each having a free margin portionspaced from the valve annulus, the aortic root movable as a function ofthe different phases of a cardiac cycle between a first rootconfiguration in which the aortic root is exposed to a diastolic phaseof the cardiac cycle and in which the leaflet free margins are in anapproximated spatial relationship to restrict blood flow therethroughand a second root configuration in which the aortic root is exposed to asystolic phase of the cardiac cycle and in which the leaflet freemargins are in a spaced apart relationship to allow blood flowtherethrough, said device comprising: an aortic conduit, said conduitbeing substantially tubular and extending in length along a longitudinaldevice axis between a first conduit end and a second conduit end; anannular ring, said annular ring coupled to said aortic conduit generallyadjacent to said conduit first end, said annular ring having a scallopedprofile including three generally U-shaped members connected to eachother and arranged around a ring axis to form a closed-perimeterstructure, said U-shaped members each having a base portion and an upperportion, said annular ring defining a first diameter proximate said baseportion and constructed to allow circumferential movement of said baseportions of said U-shaped members closer to one another such that saidannular ring defines a second diameter proximate said base portion andbeing smaller than said first diameter, said closed-perimeter structureextending in height along said device axis from said base portions tosaid upper portions of said U-shaped members; and an annulus-restrainingmember, said annulus-restraining member extending between and couplingat least two adjacent U-shaped members proximate said base portions ofsaid at least two adjacent U-shaped members; said prosthetic devicebeing configured and sized for placement externally around said aorticroot adjacent said first conduit end, and configured and sized forimplantation to the patient's ascending aorta adjacent said secondconduit end; whereby, in use, under influence of the different phases ofthe cardiac cycle, said annulus-restraining member is constructed to: 1)allow inward displacement of said U-shaped members toward said deviceaxis, the inward displacement occurring substantially without restraintfrom said annulus-restraining member and resulting in thecircumferential movement of said base portions of said U-shaped memberscloser to one another, and 2) limits maximum displacement of said baseportions of said U-shaped members away from said device axis in order toconstrain the maximum size of the aortic root so as to promotecoaptation of the leaflet free margins during the diastolic phase of thecardiac cycle.
 12. The prosthetic device of claim 11, wherein saidaortic conduit further comprises respective conduit portions betweenadjacent crest sections and, at the maximum displacement of the baseportions during the diastolic phase of the cardiac cycle, said conduitportions are configured to bulge radially outward relative to saiddevice axis.